WASHINGTON – U.S. Rep. Justin Amash returned to Twitter on Monday afternoon to defend his comments over the weekend that President Donald Trump committed impeachable offenses.

Amash, R-Cascade Township, said in a series of tweets on Monday that there does not need to be an underlying crime to warrant a charge of obstruction of justice and that a statutory charge isn't needed for Congress to move forward with impeachment anyway.

"'(High) Crimes and Misdemeanors” is not defined in the Constitution and does not require corresponding statutory charges," he wrote. "The context implies conduct that violates the public trust — and that view is echoed by the Framers of the Constitution and early American scholars."

On Saturday, Amash became the first Republican member of Congress to voice support for impeachment, saying he read the entire report of Special Counsel Robert Mueller looking into Russian interference with the 2016 election.

Mueller's report concluded that no one involved with Trump conspired with Russians but it was silent on whether he or anyone else engaged in obstruction of the investigators, saying only that, as president, he couldn't be criminally charged with that while in office.

On Sunday, Trump went on Twitter himself to call Amash a "loser" and suggest he only brought up impeachment to get attention. On Monday morning, state Rep. Jim Lower, R-Greenville, said he would run in the Republican primary for the congressional seat Amash currently holds.

Read more:

Trump calls Justin Amash 'loser' after GOP congressman remarks of impeachable offenses

Justin Amash's rise as foil to Donald Trump is no surprise

Contact Todd Spangler:tspangler@freepress.com. Follow him on Twitter@tsspangler. Read more onMichigan politics and sign up for ourelections newsletter.