US President Donald Trump's legal team on Saturday issued a resounding rejection of the House of Representatives' impeachment of him, calling the charges against Trump a "dangerous attack" on Americans and their right to vote.In a six-page document to be released on Saturday, Trump's lawyers formally address the merits of the two articles of impeachment - abuse of power and obstruction of Congress - that the Democratic-led House approved late last year and which form the basis of a trial that will begin in earnest on Tuesday in the Republican-controlled Senate, sources close to Trump's legal team said. They are planning to argue that Trump acted at all times with full constitutional legal authority, the sources added. "We are on strong legal footing. The president has done nothing wrong, and we believe that will be borne out in this process," said one of the three sources who briefed reporters on a conference call about the contents of the document.They will further argue that the articles of impeachment violate the US Constitution and would do lasting damage. Meanwhile, the US lawmakers managing the impeachment case against Donald Trump filed a brief on Saturday laying out their arguments supporting charges of abuse of power and obstruction of Congress against the president.The Democratic House of Representatives impeachment managers faced a deadline of 5 p.m. EST (2200 GMT) on Saturday to file the document, before the trial of the Republican president starts in earnest in the Senate on Tuesday.In making their case in the 111-page document, the lawmakers summarized arguments made during weeks of testimony late last year during the House impeachment investigation.They also called for Trump's removal in order to safeguard the integrity of the 2020 U.S. general election, in which Trump is seeking re-election, as well as the U.S. system of government."The country is watching to see how the Senate responds," the seven House impeachment managers said in a statement.Trump's trial brief is due at noon (1700 GMT) on Monday, and the House's reply brief is due on Tuesday at noon (1700 GMT).