



LONDON, Sept 13 (Reuters) - The U.S. economy could be $1 trillion smaller than otherwise expected in 2021 if Republican candidate Donald Trump wins the presidential election in November, economics research firm Oxford Economics said on Tuesday.

While the firm said Trump's policies - including more protectionist trade measures, tax cuts and mass deportation of illegal immigrants - may be watered down in negotiations with Congress, they could have "adverse" consequences.



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​​​​​"Should Mr. Trump prove more successful in achieving adoption of his policies, the consequences could be far-reaching - knocking 5 percent off the level of U.S. GDP relative to baseline and undermining the anticipated recovery in global growth," it said.

Oxford Economics describes itself as an independent global advisory firm. They are headquartered in Oxford, England, but have offices around the world including Chicago, Miami, Philadelphia, San Francisco and Washington.

Under its baseline scenario, Oxford Economics expects U.S. gross domestic product - the value of all goods and services produced in the economy - to grow at a fairly constant rate of around 2 percent from 2017, reaching $18.5 trillion in 2021.

Oxford Economics said its baseline scenario assumes Trump's Democratic opponent Hillary Clinton triumphs in the Nov. 8 vote and a split Congress emerges - between a Republican U.S. House of Representatives and a Democratic U.S. Senate - which results largely in a continuation of current policies.

If Trump is successful in implementing his policies, it predicts growth would slow significantly, falling near zero in 2019, and reducing overall GDP to $17.5 trillion.



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82 PHOTOS Donald Trump supporters See Gallery Donald Trump supporters Supporters cheer as U.S. President Donald Trump's motorcade passes by on his way to the airport after the Easter weekend at his Mar-a-Lago estate in Palm Beach, Florida, U.S., April 1, 2018. REUTERS/Yuri Gripas African-American supporters of U.S. President Donald Trump hold up signs as his motorcade passes through West Palm Beach, Florida, U.S., March 25, 2018. REUTERS/Joshua Roberts Supporters of U.S. President Donald Trump wave flags as his motorcade passes through West Palm Beach, Florida, U.S., March 25, 2018. REUTERS/Joshua Roberts Supporters of U.S. President Donald Trump hold a "Thank You!" banner at the annual White House Easter Egg Roll on the South Lawn of the White House in Washington, U.S., April 2, 2018. REUTERS/Carlos Barria Supporters stand with banners as U.S. President Donald Trump's motorcade passes by on his way to his Mar-A-Lago estate in West Palm Beach, Florida, U.S., March 31, 2018. REUTERS/Yuri Gripas Supporters cheer as U.S. President Donald Trump's motorcade passes by on his way to his Mar-A-Lago estate in West Palm Beach, Florida, U.S., March 31, 2018. REUTERS/Yuri Gripas Supporters cheer as U.S. President Donald Trump's motorcade passes by on his way to his Mar-A-Lago estate in West Palm Beach, Florida, U.S., March 31, 2018. REUTERS/Yuri Gripas Supporters cheer as U.S. President Donald Trump's motorcade passes by on his way to his Mar-A-Lago estate in Palm Beach, Florida, U.S., March 30, 2018. REUTERS/Yuri Gripas A supporter waves a flag as U.S. President Donald Trump's motorcade passes by on his way to his Mar-A-Lago estate in West Palm Beach, Florida, U.S., March 31, 2018. REUTERS/Yuri Gripas Supporters of U.S. President Donald Trump hold signs as his motorcade passes through West Palm Beach, Florida, U.S., March 25, 2018. REUTERS/Joshua Roberts Counter-protesters carrying signs in support of guns and Trump stand across from "March for Our Lives", an organized demonstration to end gun violence, in downtown Los Angeles, California, U.S., March 24, 2018. REUTERS/Patrick T. Fallon A U.S. President Donald Trump supporter holds up a sign at a protest to support immigration activist Ravi Ragbir across the street from the U.S. Citizenship and Immigration Services offices building in New York, U.S. March 9, 2017. REUTERS/Carlo Allegri TPX IMAGES OF THE DAY Demonstrators protest at the beach in support of U.S. President Donald Trump during a rally in Huntington Beach, California, U.S., March 25, 2017. REUTERS/Patrick T. Fallon Demonstrators send off white doves from the beach as they protest in support of U.S. President Donald Trump during a rally in Hunginton Beach, California, U.S., March 25, 2017. REUTERS/Patrick Fallon A masked supporter dances before Republican U.S. presidential candidate Donald Trump arrives at a campaign town hall event in Wausau, Wisconsin April 2, 2016. REUTERS/Ben Brewer U.S. Republican presidential candidate Donald Trump greets supporters at a campaign rally in San Jose, California, U.S. June 2, 2016. REUTERS/Lucy Nicholson Supporters cheer for U.S. Republican presidential candidate Donald Trump at a campaign rally in San Jose, California, U.S. June 2, 2016. REUTERS/Lucy Nicholson People say the pledge of allegiance before listening to U.S. Republican presidential candidate Donald Trump speak at a campaign rally in San Jose, California, U.S. June 2, 2016. REUTERS/Lucy Nicholson Supporters wait for U.S. Republican presidential candidate Donald Trump to speak at a campaign rally in San Jose, California, U.S. June 2, 2016. REUTERS/Lucy Nicholson Supporters cheer for U.S. Republican presidential candidate Donald Trump as he speaks at a campaign rally in San Jose, California, U.S. June 2, 2016. REUTERS/Lucy Nicholson Supporters (L-R) Annalisa Wales, 12, Scarlett Wales, 9, Barbara Wales, 68, and Katherine Wales, 10, wait for U.S. Republican presidential candidate Donald Trump to speak at a campaign rally in San Jose, California, U.S. June 2, 2016. REUTERS/Lucy Nicholson Supporters cheer for U.S. Republican presidential candidate Donald Trump at a campaign rally in San Jose, California, U.S. June 2, 2016. REUTERS/Lucy Nicholson U.S. Republican presidential candidate Donald Trump greets supporters at a campaign rally in San Jose, California, U.S. June 2, 2016. REUTERS/Lucy Nicholson U.S. Republican presidential candidate Donald Trump greets supporters at a campaign rally in San Jose, California, U.S. June 2, 2016. REUTERS/Lucy Nicholson U.S. Republican presidential candidate Donald Trump greets supporters at a campaign rally in San Jose, California, U.S. June 2, 2016. REUTERS/Lucy Nicholson People listen to U.S. Republican presidential candidate Donald Trump speak at a campaign rally in Sacramento, California, U.S. June 1, 2016. REUTERS/Lucy Nicholson A man carries a sign for Republican U.S. presidential candidate Donald Trump at the Rolling Thunder motorcycle rally to highlight POW-MIA issues on Memorial Day weekend in Washington, U.S. May 29, 2016. REUTERS/Jonathan Ernst People watch Republican U.S. presidential candidate Donald Trump address the Rolling Thunder motorcycle rally to highlight POW-MIA issues on Memorial Day weekend in Washington, U.S. May 29, 2016. REUTERS/Jonathan Ernst Supporters attend a rally with Republican U.S. presidential candidate Donald Trump in San Diego, California, U.S. May 27, 2016. REUTERS/Jonathan Ernst Marcos Spence solicits volunteers to work for the campaign of Republican U.S. presidential candidate Donald Trump as they stand in line before the start of his rally in Albuquerque, New Mexico, U.S. May 24, 2016. REUTERS/Jonathan Ernst A supporter holds a sign as Republican U.S. presidential candidate Donald Trump holds a rally in Anaheim, California, U.S. May 25, 2016. REUTERS/Jonathan Ernst Supporters line up to enter a convention center where U.S. Republican presidential candidate Donald Trump holds a campaign rally in Anaheim, California, United States May 25, 2016. REUTERS/Mike Blake Supporters of Republican U.S. Presidential candidate Donald Trump arrive before Trump speaks at a campaign event in Anaheim, California U.S. May 25, 2016. REUTERS/Mike Blake A supporter of Republican U.S. Presidential candidate Donald Trump holds a sign before Trump speaks at a campaign event in Anaheim, California U.S. May 25, 2016. REUTERS/Mike Blake Supporters of Republican U.S. Presidential candidate Donald Trump arrive before Trump speaks at a campaign event in Anaheim, California U.S. May 25, 2016. REUTERS/Mike Blake Supporters of Republican U.S. presidential candidate Donald Trump stand in line before the start of his rally in Albuquerque, New Mexico, U.S. May 24, 2016. REUTERS/Jonathan Ernst FOR EDITORIAL USE ONLY. NO RESALES. NO ARCHIVES. A supporter of Republican U.S. presidential candidate Donald Trump attends a Trump campaign rally at the Verizon Wireless Arena in Manchester, New Hampshire, February 8, 2016. REUTERS/Rick Wilking A supporter of Republican U.S. presidential candidate Donald Trump wearing a "Trump for President '16" t-shirt listens to the candidate speak at a campaign rally at the airport in Hagerstown, Maryland, U.S. On April 24, 2016. REUTERS/Jim Bourg/File Photo Activists of Hindu Sena, a Hindu right-wing group, perform a special prayer to ensure a victory of Republican U.S. presidential candidate Donald Trump in the upcoming elections, according to a media release, in New Delhi, India May 11, 2016. REUTERS/Anindito Mukherjee Supporters hold signs as Republican U.S. presidential candidate Donald Trump speaks during a campaign rally in Lynden, Washington, U.S., May 7, 2016. REUTERS/Jim Urquhart Supporters cheer as Republican U.S. presidential candidate Donald Trump speaks during a campaign rally in Lynden, Washington, U.S., May 7, 2016. REUTERS/Jim Urquhart Supporters hold signs as Republican U.S. presidential candidate Donald Trump speaks during a campaign rally in Lynden, Washington, U.S., May 7, 2016. REUTERS/Jim Urquhart Delegate Douglas Marshall in the Donald Trump booth during the second day of the Republican Party of Texas state convention on May 13, 2016 in Dallas. (Paul Moseley/Fort Worth Star-Telegram/TNS via Getty Images) A supporter of U.S. Republican presidential candidate Donald Trump holds a sign during a campaign event at Grumman Studios in Bethpage, New York April 6, 2016. REUTERS/Shannon Stapleton A supporter of U.S. Republican presidential candidate Donald Trump takes a photo during a campaign event at Grumman Studios in Bethpage, New York April 6, 2016. REUTERS/Shannon Stapleton Republican U.S. presidential candidate Donald Trump supporters Josh (R), and his father Jeff Schimek (L), wait for him to speaks during a Town Hall at the Racine Civic Centre Memorial Hall April 2, 2016. REUTERS/Kamil Krzaczynski EDITORIAL USE ONLY. NO RESALES. NO ARCHIVE Supporters (L) of Republican U.S. presidential candidate Donald Trump point and scream at an anti-Trump demonstrator (R) holding a sign reading "More Like Make America Racist Again" sign during a Trump campaign rally in Fountain Hills, Arizona March 19, 2016. REUTERS/Ricardo Arduengo TPX IMAGES OF THE DAY A supporter of U.S. Republican presidential candidate Donald Trump attends a campaign rally in De Pere, Wisconsin, United States, March 30, 2016. REUTERS/Jim Young Bob Bolus, a supporter of U.S. Republican presidential candidate Donald Trump, gives the thumbs up to drivers as they pass by on Super Tuesday in Middleburg Heights, Ohio March 15, 2016. REUTERS/Aaron Josefczyk Rosemary Harder wears a hat supporting Republican U.S. presidential candidate Donald Trump during a news conference, after the Florida, Ohio, North Carolina, Illinois and Missouri primary elections, held at his Mar-A-Lago Club, in Palm Beach, Florida March 15, 2016. REUTERS/Joe Skipper Supporter of U.S. Republican presidential candidate Donald Trump Alex Stypik joins Trump (L) on stage at a campaign rally in Bloomington, Illinois March 13, 2016. REUTERS/Jim Young A Trump supporter (R) yells at a demonstrator (L) after Republican U.S. presidential candidate Donald Trump cancelled his rally at the University of Illinois at Chicago March 11, 2016. REUTERS/Kamil Krzaczynski TPX IMAGES OF THE DAY Supporters of Republican U.S. presidential candidate Donald Trump cheer on their candidate at a Trump campaign rally in New Orleans, Louisiana March 4, 2016. REUTERS/Layne Murdoch Jr. A supporter of U.S. Republican presidential candidate Donald Trump attends a campaign rally in Cadillac, Michigan, March 4, 2016. REUTERS/Jim Young A supporter of Republican U.S. presidential candidate Donald Trump holds up a sign at a campaign rally at Valdosta State University in Valdosta, Georgia February 29, 2016. REUTERS/ Philip Sears A supporter of Republican U.S. presidential candidate Donald Trump celebrates with a cigar at Trump's 2016 South Carolina presidential primary night rally in Spartanburg, South Carolina February 20, 2016. REUTERS/Jonathan Ernst A campaign volunteer for U.S. Republican presidential candidate Donald Trump wears a hat signed by Trump during a rally with supporters in Gaffney, South Carolina February 18, 2016. REUTERS/Jonathan Ernst Freda Green, of Louisiana, wears a hat in support of Republican U.S. presidential candidate Donald Trump before a rally in Baton Rouge, Louisiana February 11, 2016. REUTERS/Jonathan Bachman A veteran of both the Korean and the Vietnam War, C.J. Dauzt wears a sticker in support of Republican U.S. presidential candidate Donald Trump before a rally in Baton Rouge, Louisiana in Baton Rouge, Louisiana February 11, 2016. REUTERS/Jonathan Bachman 10-year-old Ian Linden, of New Orleans, holds a sign in support of Republican U.S. presidential candidate Donald Trump before a rally in Baton Rouge, Louisiana February 11, 2016. REUTERS/Jonathan Bachman Supporter of U.S. Republican presidential candidate Donald Trump wait for the start of his campaign rally in Plymouth, New Hampshire February 7, 2016. REUTERS/Jim Bourg Anne-Sophie Marquis cradles her doll Clare, wearing a button supporting U.S. Republican presidential candidate Donald Trump, at a Trump campaign rally in Plymouth, New Hampshire February 7, 2016. REUTERS/Rick Wilking Young supporters of Republican U.S. presidential candidate businessman Donald Trump wait for Trump to speak at a veteran's rally in Des Moines, Iowa January 28, 2016. REUTERS/Aaron P. Bernstein Mark Palzer shows his support for U.S. Republican presidential candidate Donald Trump before a campaign rally at Oral Roberts University in Tulsa, Oklahoma January 20, 2016. REUTERS/Nick Oxford Barbara Tomasino shows her support for U.S. Republican presidential candidate Donald Trump before a campaign rally at Oral Roberts University in Tulsa, Oklahoma, January 20, 2016. REUTERS/Nick Oxford Supporters of U.S. Republican presidential candidate Donald Trump attend a campaign rally at Oral Roberts University in Tulsa, Oklahoma, January 20, 2016. REUTERS/Nick Oxford Liberty University students and supporters of Republican presidential candidate Donald Trump wear letters spelling his name before his speech at Liberty University in Lynchburg, Virginia, January 18, 2016. REUTERS/Joshua Roberts A supporter of U.S. Republican presidential candidate Donald Trump wears a National Rifle Association shirt before his speech at Liberty University in Lynchburg, Virginia, January 18, 2016. REUTERS/Joshua Roberts Trump supporters Joshua Smith (from Left) and Seth Stephens, both of Aiken, South Carolina and Rona Bartolomucci of Hilton Head Island, wait along the front buffer before a rally for U.S. Republican presidential candidate Donald Trump at the Westin Hilton Head Island Resort and Spa in Hilton Head Island, South Carolina, December 30, 2015. REUTERS/Randall Hill FOUNTAIN HILLS, AZ - MARCH 19: Supporters of Republican presidential candidate Donald Trump look on during Fountain Park during a campaign rally on March 19, 2016 in Fountain Hills, Arizona. Trumps visit to Arizona is the second time in three months as he looks to gain the GOP nomination for President. (Photo by Ralph Freso/Getty Images) SALT LAKE CITY, UT - MARCH 18: A supporter waits for Republican presidential candidate Donald Trump speak at a campaign rally on March 18, 2016 in Salt Lake City, Utah. The Republican and Democratic caucuses are March 22. (Photo by George Frey/Getty Images) A supporter of Donald Trump, president and chief executive of Trump Organization Inc. and 2016 Republican presidential candidate, wears campaign stickers on her sandals before a town hall event at the Tampa Convention Center in Tampa, Florida, U.S., on Monday, March 14, 2016. As protesters shadow campaign appearances by Trump, the billionaire has shifted a planned Monday-night rally in south Florida to Ohio, where polls show Governor John Kasich may be pulling ahead days before the states primary election. Photographer: Andrew Harrer/Bloomberg via Getty Images Trump supporters pass out signs prior to a rally for Republican presidential candidate Donald Trump on March 13, 2016 in Boca Raton, Florida. Primary voters head to the polls on March 15th in Florida. / AFP / RHONA WISE (Photo credit should read RHONA WISE/AFP/Getty Images) Attendees wait for the start of a campaign event with Donald Trump, president and chief executive of Trump Organization Inc. and 2016 Republican presidential candidate, not pictured, in Bloomington, Illinois, U.S., on Sunday, March 13, 2016. After violent protests prompted Donald Trump to cancel a rally in Chicago on Friday night, the Republican presidential front-runner blamed the activist group MoveOn.Org and supporters of Senator Bernie Sanders for the chaos, while defending his own harassed supporters. Photographer: Daniel Acker/Bloomberg via Getty Images Donald Trump, president and chief executive of Trump Organization Inc. and 2016 Republican presidential candidate, left, stands with a man he called onto the stage from the crowd because of the 'Legal Immigrant For Trump' t-shirt he was wearing, during a campaign event in Bloomington, Illinois, U.S., on Sunday, March 13, 2016. After violent protests prompted Donald Trump to cancel a rally in Chicago on Friday night, the Republican presidential front-runner blamed the activist group MoveOn.Org and supporters of Senator Bernie Sanders for the chaos, while defending his own harassed supporters. Photographer: Daniel Acker/Bloomberg via Getty Images CHICAGO, IL - MARCH 11: A supporter exists the University of Illinois at Chicago Pavilion where Republican presidential candidate Donald Trump cancelled a campaign rally over safety concerns March 11, 2016 in Chicago, Illinois. The Illinois Republican presidential primary will be held March 15. (Photo by Jonathan Gibby/Getty Images) Supporters of Republican Presidential candidate Donald Trump gather prior to a Trump Rally at the Peabody Opera House on March 11, 2016 in St. Louis, Missouri. / AFP / Michael B. Thomas (Photo credit should read MICHAEL B. THOMAS/AFP/Getty Images) Supporters of Republican Presidential candidate Donald Trump gather prior to a Trump Rally at the Peabody Opera House on March 11, 2016 in St. Louis, Missouri. / AFP / Michael B. Thomas (Photo credit should read MICHAEL B. THOMAS/AFP/Getty Images) RADFORD, VA - FEBRUARY 29: A campaign rally for Donald J. Trump, candidate for the Republican presidential nomination, at the Radford University Dedmon Arena in Radford, Virginia, on Monday, February 29, 2016. (Photo by Benjamin Lowy/Getty Images Reportage) A woman reacts as U.S. Republican presidential candidate Donald Trump works the crowd following a campaign event in an airplane hanger in Rome, New York April 12, 2016. REUTERS/Carlo Allegri A woman reacts as U.S. Republican presidential candidate Donald Trump works the crowd following a campaign event in an airplane hanger in Rome, New York April 12, 2016. REUTERS/Carlo Allegri Supporters cheer as U.S. President Donald Trump's motorcade passes by on his way to his Mar-A-Lago estate in Palm Beach, Florida, U.S., March 30, 2018. REUTERS/Yuri Gripas Up Next See Gallery Discover More Like This HIDE CAPTION SHOW CAPTION of SEE ALL BACK TO SLIDE

Trump would face challenges winning the backing of Congress for all his policies, and some economists argue that looser tax policy could actually help boost economic growth.

The latest opinion polls show Clinton, the former secretary of state, ahead, but her lead has slipped in recent weeks. (Reporting by John Geddie; Editing by Jamie McGeever and Howard Goller)

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