(CNN) As a New York businessman, Donald Trump proudly referred to himself as the "King of Debt" -- he thrived on taking financial risks and routinely leveraged debt to grow his family empire.

"I'm the king of debt. I love debt," Trump told CNN's Wolf Blitzer in May 2016 at the height of the campaign -- blunt and telling comments that revealed just how comfortable the real estate mogul was in using debt as a financial tool.

But now, the mindset behind that nickname is aggravating some of the President's Republican colleagues in Washington.

As GOP lawmakers are struggling to enact an agenda of spending and tax reform , they continue to face the painful reminder that Trump has no ideological drive to tame the deficit. The President has made clear that he doesn't mind if deep tax cuts result in a ballooning of the national debt. He is not pre-occupied with offsetting new spending; and he is entirely comfortable with a clean raising of the debt ceiling.

Trump's statements have also raised questions about his understanding of the national debt. In a recent interview with Fox News' Sean Hannity , Trump suggested that gains in the stock market have led to a reduction in the national debt. "We picked up $5.2 trillion just in the stock market," he said. "So you can say in one sense, we are really increasing values and may be in a sense, we are reducing debt."

And the coming days are about to present the most extended test of Trump's fiscal instincts. With the passage of the budget resolution Thursday night, Republicans will now squarely turn their attention to tax reform.

'Getting stuff done'

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Kathy Wylde, president and CEO of Partnership for New York City, a prominent business coalition, said Trump is simply not as ideological as some Republicans when it comes to spending.

"Business people, New Yorkers -- that's what they're comfortable with. Getting stuff done as opposed to pursuing an abstract, ideological agenda," Wylde said. Unlike some GOP lawmakers, she added, "they're not there to uphold abstract principles."

In fact, Trump has recounted his personal run-ins with debt in his various autobiographies. Owing money to powerful individuals and institutions marked some of the lowest -- and most unpleasant -- moments of Trump's career.

In the book "Think Big and Kick Ass in Business and Life," co-written with Bill Zanker, Trump described being in "deep, deep" financial trouble in the early 1990s.

"It was not exactly fun," Trump wrote. "Believe me, it is not cool to be Donald Trump when you owe billions of dollars."

He recalled a bankers' convention at the Waldorf Astoria hotel in New York City and feeling little desire to attend. When he decided at the last minute to make an appearance, he encountered a banker in charge of collecting loans whom he described as being especially "mean and nasty."

"I was miserable," Trump said.

But as the night wore on and the two men chatted, Trump said the conversation became enjoyable. At the end of the evening, the banker said to Trump, "You know what, Donald, you're not a bad guy!"

To his delight, the banker extended an invitation to visit his office to work something out, Trump wrote.

"Monday morning I went to his office, and in five minutes, we had worked out a great deal," he said.

Long-held view

Photos: Donald Trump's rise President-elect Donald Trump has been in the spotlight for years. From developing real estate and producing and starring in TV shows, he became a celebrity long before winning the White House. Hide Caption 1 of 37 Photos: Donald Trump's rise Trump at age 4. He was born in 1946 to Fred and Mary Trump in New York City. His father was a real estate developer. Hide Caption 2 of 37 Photos: Donald Trump's rise Trump, left, in a family photo. He was the second-youngest of five children. Hide Caption 3 of 37 Photos: Donald Trump's rise Trump, center, stands at attention during his senior year at the New York Military Academy in 1964. Hide Caption 4 of 37 Photos: Donald Trump's rise Trump, center, wears a baseball uniform at the New York Military Academy in 1964. After he graduated from the boarding school, he went to college. He started at Fordham University before transferring and later graduating from the Wharton School, the University of Pennsylvania's business school. Hide Caption 5 of 37 Photos: Donald Trump's rise Trump stands with Alfred Eisenpreis, New York's economic development administrator, in 1976 while they look at a sketch of a new 1,400-room renovation project of the Commodore Hotel. After graduating college in 1968, Trump worked with his father on developments in Queens and Brooklyn before purchasing or building multiple properties in New York and Atlantic City, New Jersey. Those properties included Trump Tower in New York and Trump Plaza and multiple casinos in Atlantic City. Hide Caption 6 of 37 Photos: Donald Trump's rise Trump attends an event to mark the start of construction of the New York Convention Center in 1979. Hide Caption 7 of 37 Photos: Donald Trump's rise Trump wears a hard hat at the Trump Tower construction site in New York in 1980. Hide Caption 8 of 37 Photos: Donald Trump's rise Trump was married to Ivana Zelnicek Trump from 1977 to 1990, when they divorced. They had three children together: Donald Jr., Ivanka and Eric. Hide Caption 9 of 37 Photos: Donald Trump's rise The Trump family, circa 1986. Hide Caption 10 of 37 Photos: Donald Trump's rise Trump uses his personal helicopter to get around New York in 1987. Hide Caption 11 of 37 Photos: Donald Trump's rise Trump stands in the atrium of the Trump Tower. Hide Caption 12 of 37 Photos: Donald Trump's rise Trump attends the opening of his new Atlantic City casino, the Taj Mahal, in 1989. Hide Caption 13 of 37 Photos: Donald Trump's rise Trump signs his second book, "Trump: Surviving at the Top," in 1990. Trump has published at least 16 other books, including "The Art of the Deal" and "The America We Deserve." Hide Caption 14 of 37 Photos: Donald Trump's rise Trump and singer Michael Jackson pose for a photo before traveling to visit Ryan White, a young child with AIDS, in 1990. Hide Caption 15 of 37 Photos: Donald Trump's rise Trump dips his second wife, Marla Maples, after the couple married in a private ceremony in New York in December 1993. The couple divorced in 1999 and had one daughter together, Tiffany. Hide Caption 16 of 37 Photos: Donald Trump's rise Trump putts a golf ball in his New York office in 1998. Hide Caption 17 of 37 Photos: Donald Trump's rise An advertisement for the television show "The Apprentice" hangs at Trump Tower in 2004. The show launched in January of that year. In January 2008, the show returned as "Celebrity Apprentice." Hide Caption 18 of 37 Photos: Donald Trump's rise A 12-inch talking Trump doll is on display at a toy store in New York in September 2004. Hide Caption 19 of 37 Photos: Donald Trump's rise Trump attends a news conference in 2005 that announced the establishment of Trump University. From 2005 until it closed in 2010, Trump University had about 10,000 people sign up for a program that promised success in real estate. Three separate lawsuits -- two class-action suits filed in California and one filed by New York's attorney general -- argued that the program was mired in fraud and deception. Trump's camp rejected the suits' claims as "baseless." And Trump has charged that the New York case against him is politically motivated. Hide Caption 20 of 37 Photos: Donald Trump's rise Trump attends the U.S. Open tennis tournament with his third wife, Melania Knauss-Trump, and their son, Barron, in 2006. Trump and Knauss married in 2005. Hide Caption 21 of 37 Photos: Donald Trump's rise Trump wrestles with "Stone Cold" Steve Austin at WrestleMania in 2007. Trump has close ties with the WWE and its CEO, Vince McMahon. Hide Caption 22 of 37 Photos: Donald Trump's rise For "The Apprentice," Trump was honored with a star on the Hollywood Walk of Fame in January 2007. Hide Caption 23 of 37 Photos: Donald Trump's rise Trump appears on the set of "The Celebrity Apprentice" with two of his children -- Donald Jr. and Ivanka -- in 2009. Hide Caption 24 of 37 Photos: Donald Trump's rise Trump poses with Miss Universe contestants in 2011. Trump had been executive producer of the Miss Universe, Miss USA and Miss Teen USA pageants since 1996. Hide Caption 25 of 37 Photos: Donald Trump's rise In 2012, Trump announces his endorsement of Republican presidential candidate Mitt Romney. Hide Caption 26 of 37 Photos: Donald Trump's rise Trump speaks in Sarasota, Florida, after accepting the Statesman of the Year Award at the Sarasota GOP dinner in August 2012. It was shortly before the Republican National Convention in nearby Tampa. Hide Caption 27 of 37 Photos: Donald Trump's rise Trump appears on stage with singer Nick Jonas and television personality Giuliana Rancic during the 2013 Miss USA pageant. Hide Caption 28 of 37 Photos: Donald Trump's rise In June 2015, during a speech from Trump Tower, Trump announced that he was running for President. He said he would give up "The Apprentice" to run. Hide Caption 29 of 37 Photos: Donald Trump's rise Trump -- flanked by U.S. Sens. Marco Rubio, left, and Ted Cruz -- speaks during a CNN debate in Miami on March 10. Trump dominated the GOP primaries and emerged as the presumptive nominee in May. Hide Caption 30 of 37 Photos: Donald Trump's rise The Trump family poses for a photo in New York in April. Hide Caption 31 of 37 Photos: Donald Trump's rise Trump speaks during a campaign event in Evansville, Indiana, on April 28. After Trump won the Indiana primary, his last two competitors dropped out of the GOP race. Hide Caption 32 of 37 Photos: Donald Trump's rise Trump delivers a speech at the Republican National Convention in July, accepting the party's nomination for President. "I have had a truly great life in business," he said. "But now, my sole and exclusive mission is to go to work for our country -- to go to work for you. It's time to deliver a victory for the American people." Hide Caption 33 of 37 Photos: Donald Trump's rise Trump faces Democratic nominee Hillary Clinton in the first presidential debate, which took place in Hempstead, New York, in September. Hide Caption 34 of 37 Photos: Donald Trump's rise Trump apologizes in a video, posted to his Twitter account in October, for vulgar and sexually aggressive remarks he made a decade ago regarding women. "I said it, I was wrong and I apologize," Trump said, referring to lewd comments he made during a previously unaired taping of "Access Hollywood." Multiple Republican leaders rescinded their endorsements of Trump after the footage was released. Hide Caption 35 of 37 Photos: Donald Trump's rise Trump walks on stage with his family after he was declared the election winner on November 9. "Ours was not a campaign, but rather, an incredible and great movement," he told his supporters in New York. Hide Caption 36 of 37 Photos: Donald Trump's rise Trump is joined by his family as he is sworn in as President on January 20. Hide Caption 37 of 37

Trump's long-held view that debt, above all else, is a useful tool to strike deals and turn profits has clearly shaped his policy positions as president.

The first clear sign of this came last month, when to the surprise of his Republican colleagues on Capitol Hill, Trump abruptly announced a deal with Democratic leaders in part to raise the debt ceiling for three months. There was no discussion about spending cuts to offset the hike.

The sudden agreement caught even some of Trump's top aides by surprise. It was particularly awkward for Trump's director of the Office of Management and Budget, Mick Mulvaney, the former GOP congressman who had famously railed against clean debt hikes.

Pressed by reporters at the time on whether he would have voted for the bill if he were still in the House, Mulvaney repeatedly demurred

And now, as he desperately looks to score a legislative victory before the end of the year, Trump is pledging "the largest tax cut in the history of our country" -- again, without batting an eye at the reality that such steep cuts would grow the national debt.

Trump's seeming lack of interest in trying to keep the deficit in check has exasperated -- and alarmed -- some conservatives.

Kori Schake, a fellow at the Hoover Institution who has worked at the National Security Council and the Defense Department, said this week that "the most alarming thing to me about the Trump administration" is its argument that "debt shouldn't matter at all and that economic growth is going to take care of this problem."

Tennessee Republican Sen. Bob Corker has also made clear his displeasure.

"I'm very concerned, as everyone knows, and have been for ten years and nine months since I've been here about our deficits," Corker, who recently announced he would retire at the end of his current term, told CNN this week. "I want to make sure that it's not something that increases deficits."

Still, the most outspoken fiscal hawks on Capitol Hill appear unlikely to get support from the President on ensuring that spending cuts are included in a tax reform plan.

Former Republican Oklahoma Gov. Frank Keating said GOP lawmakers might be better off simply accepting that the President is untethered to many traditionally conservative ideological bearings.

"He's not a traditional politician and he's not a Republican in any historic sense. So Republicans are going to have to realize that," Keating said of Trump. "I think some of the purists on the Republican side don't understand that yet."