Three weeks after pointedly refusing to endorse Donald Trump, House Speaker Paul Ryan backed down on Thursday and announced his support.

“It’s no secret that he and I have our differences,” Ryan wrote in an op-ed on GazetteXtra.com. “I won’t pretend otherwise. And when I feel the need to, I’ll continue to speak my mind. But the reality is, on the issues that make up our agenda, we have more common ground than disagreement.”

A Republican source close to Ryan said he made the decision to endorse early this week following a series of conversations with Trump over the last several weeks. While Ryan will focus on campaigning for fellow House members, the source did not rule out the possibility he would join Trump on the campaign trail or help fundraise for his campaign.