FILE PHOTO: U.S. President Donald Trump speaks at the American Farm Bureau Federation's Annual Convention and Trade Show in Austin, Texas, January 19, 2020. REUTERS/Kevin Lamarque

WASHINGTON (Reuters) - President Donald Trump’s lawyers argued on Monday that the impeachment case against him is a product of a rigged process by Democrats and “must be rejected” in the Senate trial that gets under way in earnest on Tuesday.

An executive summary of Trump’s pre-trial brief for the Senate proceedings urges the Republican-led Senate to quickly acquit the president on two articles of impeachment approved against him by the Democratic-controlled House of Representatives.

“The Senate should speedily reject these deficient articles of impeachment and acquit the president,” said the summary, released on Monday.

It called the charges an “affront to the Constitution and our democratic institutions,” and said the obstruction of Congress charge was “frivolous and dangerous.”