For months, Rep. Jeff Van Drew, a freshman Democrat from New Jersey, has publicly trashed the impeachment process, calling it unfair, unfounded, and deeply damaging to the country—but privately, this soon-to-be Republican had a much different reasoning.

Behind closed doors, Van Drew has told colleagues that the president was stupid and mentally unstable—and that his opposition to impeachment stemmed from his belief that impeaching Trump would ensure his re-election, according to two Democrats present at closed-door discussions with the congressman.

A third verified Van Drew had disparaged the president in harsh terms, calling him “crazy.”

“He was almost obsessively anti-Trump,” said one of the Democrats. “His only justification, and this was adamant, was that he thinks that [impeachment] will help Trump win.”

Van Drew’s office did not immediately respond to a request for comment.

His apparent disdain for Trump makes the New Jersey Democrat’s decision to switch parties this week even more puzzling. But on Tuesday afternoon even that started to seem in doubt.

In an interview with the Philadelphia Inquirer, Van Drew said he was “reevaluating my life and my thoughts” but confirmed he would be seeking reelection to his southern New Jersey seat in 2020. He later declined to tell reporters if he would even switch parties at all, saying he was “thinking” about it and would reveal a decision soon.

There are plenty of officials in the Republican Party who have criticized the president in private but have held their fire, or even praised him, in public. But it’s particularly striking for Van Drew, who has made a high-profile decision to leave his party out of protest over Trump’s impeachment—and who needs the president's support, and the support of the GOP, if he is to retain his seat in Congress.

The New York Times reported on Saturday that Van Drew went to the White House and explicitly sought Trump’s blessing to defect to the GOP, a move the president urged him to make. Early Tuesday morning, Trump tweeted that Van Drew “is very popular in our great and very united Republican Party. It was a tribute to him that he was able to win his heavily Republican district as a Democrat. People like that are not easily replaceable!”