Rep. Justin Amash (I-Mich.), who recently left the Republican Party, said President Trump's "demagoguery" is to blame for the crowd at the president's rally chanting "send her back" about Rep. Ilhan Omar (D-Minn.).

"A chant like 'Send her back!' 'is ugly and dangerous, and it is the inevitable consequence of President Trump's demagoguery," Amash tweeted Thursday. "This is how history's worst episodes begin. We must not allow this man to take us to such a place."

The chant at Wednesday night's rally in North Carolina followed days of Trump doubling down on his attacks on freshman Democratic Reps. Omar, Alexandria Ocasio-Cortez (N.Y.), Rashida Tlaib (Mich.) and Ayanna Pressley (D-Mass.).

He tweeted that the lawmakers, all women of color, should "go back" where they came from. Only Omar was born outside of the U.S.

Amash voted for a House resolution earlier this week to condemn Trump's tweets as racist.

Just four Republicans joined all Democrats in backing the resolution.

Before Amash left the GOP over differences with Trump and the direction the party was taking, he was the only Republican to publicly support impeachment. He has said he is not ruling out a potential 2020 presidential run.

Former Massachusetts Gov. Bill Weld (R), who has mounted a primary campaign against Trump, also tweeted criticism of the "send her back" chants. Weld said Republicans are in a "fight for the soul of the GOP."