Republican strategist Steve Schmidt, a senior adviser to the presidential campaign of Sen. John McCain (Ariz.), announced early Wednesday that he is leaving the Republican Party, which he decried as “fully the party of Trump” and “a danger to our democracy and values.”

In early-morning tweets, Schmidt, a vocal Trump critic, urged voters to elect Democrats in the 2018 midterm elections and harshly criticized the administration’s policy of separating migrant children from their parents at the U.S. border, describing the government-run detention centers as “internment camps for babies.”

“29 years and nine months ago I registered to vote and became a member of The Republican Party which was founded in 1854 to oppose slavery and stand for the dignity of human life,” Schmidt wrote. “Today I renounce my membership in the Republican Party. It is fully the party of Trump.”

After Trump’s contentious appearance at the Group of Seven summit in Canada this month, Schmidt condemned Republican Party leaders for not being more critical of the president. On Wednesday, Schmidt doubled down on that criticism, saying that with the exception of Republican governors Charlie Baker of Massachusetts, Larry Hogan of Maryland and John Kasich of Ohio, the Republican Party is “filled with feckless cowards who disgrace and dishonor the legacies of the party’s greatest leaders.”

All three governors have denounced the Trump administration’s separation policy.

“This child separation policy is connected to the worst abuses of humanity in our history,” Schmidt wrote. “It is connected by the same evil that separated families during slavery and dislocated tribes and broke up Native American families. It is immoral and must be repudiated. Our country is in trouble. Our politics are badly broken.”

“The first step to a season of renewal in our land is the absolute and utter repudiation of Trump and his vile enablers in the 2018 election by electing Democratic majorities,” Schmidt added.

In recent months, Schmidt has become increasingly critical of Trump and the Republican Party. In November, he encouraged voters in Alabama to elect Democrat Doug Jones over Republican nominee Roy Moore.

Schmidt served as a top aide in the administration of President George W. Bush.

In his new memoir, co-written with longtime adviser Mark Salter, McCain wrote that Schmidt urged him in 2008 to select then-Alaska Gov. Sarah Palin as his running mate — a move that some argue paved the way for Trump’s eventual political rise.

“Schmidt made the case for her, which essentially boiled down to ‘she could shake up the race and the other candidates can’t,’” McCain wrote. “She was a fresh face, an outspoken reformer, a wife and mother who had fought the special interests and won.”