We may earn a commission from links on this page.

Using their own criticisms of Donald Trump as ammunition, US president Barack Obama on Aug. 2 called on Republican leaders to withdraw support for their presidential nominee, saying he is “unfit to serve as president.”

“This is not just my opinion,” Obama said during a press conference at the White House. “I think what’s been interesting is the repeated denunciations of his statements by leading Republicans … If you are repeatedly having to say in very strong terms that what he has said is unacceptable, why are you still endorsing him?”

The intra-party criticism has been building since Trump declared his candidacy more than a year ago, starting with the June 2015 speech in which he described Mexican immigrants as rapists bringing drugs and crime to the US. But it seemingly reached a crescendo this week after Trump attacked the parents of a Muslim US soldier who was killed in Iraq, after they appeared at the Democratic National Convention.

One of the strongest rebukes against Trump came from Republican senator John McCain of Arizona, who was the party’s nominee in the 2008 election. “It is time for Donald Trump to set the example for our country and the future of the Republican Party. While our Party has bestowed upon him the nomination, it is not accompanied by unfettered license to defame those who are the best among us,” he said. McCain, who pledged in May that he would back his party’s nominee, stopped short of withdrawing his support.

But at least one Republican legislator has publicly announced a decision to vote for Trump’s Democratic rival. In a letter published by Syracuse.com on Aug. 1, Richard Hanna, a US congressman from the state of New York, became the first federal Republican lawmaker to publicly endorse Hillary Clinton. “While I disagree with her on many issues, I will vote for Mrs. Clinton,” he wrote. “I will be hopeful and resolute in my belief that being a good American who loves his country is far more important than parties or winning and losing.”

Hanna has publicly criticized Trump on numerous occasions, and vowed in March not to support him.

“My reasons were simple and personal,” he wrote in his Aug. 1 commentary. “I found him profoundly offensive and narcissistic but as much as anything, a world-class panderer, anything but a leader. Little more than a changing mirror of those he speaks to. I never expect to agree with whoever is president, but at a minimum the president needs to consistently display those qualities I have preached to my two children: kindness, honesty, dignity, compassion and respect.”