Lindsey Graham, the Republican senator and Trump ally, alleged that impeachment proceedings are a "war on the presidency" by Democrats, hours before the Senate trial begins on Tuesday.
Mr Graham, speaking almost a month after Trump supporters besieged the US Capitol with baseless allegations the presidential election was “stolen” by Democrats, said the party “basically declared war on the presidency."
The South Carolina senator on Monday told Fox News’s anchor Sean Hannity that Democrats were waging a “war on the presidency” because witnesses were not called when the House voted last month to impeach.
The Republican, copying claims made by Mr Trump’s legal team on the same day, also claimed the Senate trial was unconstitutional.
Democrats argue that Mr Trump's remarks on the day the Capitol riot took place were public and clear and so there was overwhelming evidence to support the single impeachment article — alleging Mr Trump’s “incitement of insurrection” on 6 January.
"The impeachment in the House took place without a hearing, without one witness being called, and without a lawyer for the president of the United States," said Mr Graham on Monday.
"You can't get a traffic ticket based on what they used to impeach president Trump," he continued, and claimed the trial was unconstitutional because Mr Trump wasn’t president anymore.
“When you combine a snap impeachment with an impeachment of a president who is out of office, you’re going to destroy the presidency,” Mr Graham said, while complaining about “never ending impeachments” and “due process”.
Democratic impeachment managers responded to Mr Trump's legal team on Monday and said the “evidence of president Trump’s conduct is overwhelming”.
“He has no valid excuse or defence for his actions, and his efforts to escape accountability are entirely unavailing,” they added in a separate memo.
While as many as ten Republicans voted with House Democrats to impeach the former president last month, there is only a remote possibility that Senators will vote to convict Mr Trump at the end of the trial.
Adam Kissinger, a House Republican, argued in a Washington Post op-ed on Monday that his Senate colleagues should support Democrats and convict Mr Trump as a matter of “accountability” for the events of 6 January, which left at least people dead.
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