After weeks of withholding his support, Speaker of the House Paul Ryan announced Thursday he plans to vote for Donald Trump for president this fall.

Ryan’s endorsement is a major step toward the entire GOP unifying around Trump as its nominee, and ends speculation that the nation’s top-elected Republican might not back his party’s candidate for president.

In an op-ed published in a local Wisconsin newspaper, the Badger State congressman cited the policy agenda he and House Republicans have been developing this year and said conversations with Trump about that agenda persuaded him to endorse.

“Through these conversations, I feel confident [Trump] would help us turn the ideas in this agenda into laws to help improve people’s lives. That’s why I’ll be voting for him this fall,” Ryan wrote.

The endorsement comes one month after Ryan shocked the political world by saying he wasn’t yet prepared to back his party’s nominee.

Since then, the two men have spoken multiple times, including at a highly publicized meeting brokered by Republican National Committee Chairman Reince Priebus. Many Republicans believed Ryan would eventually announce his support, but the speaker continued throughout May to say he wasn’t prepared to back the party’s presumptive nominee.

A source close to Ryan said he last spoke with Trump last week, and made the decision to endorse him earlier this week. The source said it was too early to predict whether Ryan would actively campaign for or raise money with Trump, or to predict what the speaker’s role as chair of the Republican National Convention would look like. The source added that Ryan’s focus remains on helping House Republicans to maintain their majority.

A spokesperson for Trump did not immediately respond to a request for comment.

Ryan said Thursday he’s talked with Trump “at great length” about broad GOP principles including limits on executive power and the importance of pro-life beliefs, but that the main focus of their conversations has been the policies Ryan is promoting, include reducing poverty, repealing and replacing the Affordable Care Act, tax reform, strong national security, and setting clear standards on executive overreach.

House Republicans have developed task forces to tackle these different issues and Ryan said they plan to roll out this policy agenda over the next month, starting with a plan to fight poverty that will be released next week. Ryan indicated that Trump would be supportive of that agenda.

“For me, it’s a question of how to move ahead on the ideas that I—and my House colleagues—have invested so much in through the years,” Ryan said. “It’s not just a choice of two people, but of two visions for America. And House Republicans are helping shape that Republican vision by offering a bold policy agenda, by offering a better way ahead.”

The source close to Ryan said the policies have been “fairly fleshed out” and that Trump is aware of policy details, not just broad ideas. The source said there was mostly a discussion of areas where there is broad agreement, and not about things where there is significant disagreement between Ryan and Trump, including immigration. 

While Ryan avoided weighing in fully on the presidential race while the primary was competitive, he did speak out against Trump multiple times before the business mogul won the nomination, including denouncing Trump’s call to ban Muslims from entering the country and the fact that he didn’t immediately disavow the backing of David Duke, the former leader Ku Klux Klan leader. Despite now backing Trump to become the most powerful man in the world, Ryan said he would continue to speak out if similar issues arise during the campaign.

“It’s no secret that he and I have our differences,” Ryan said of Trump. “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.”

Ryan’s announcement came as likely Democratic nominee Hillary Clinton was delivering a major foreign policy address in which she questioned Trump’s ability and credentials to lead the United States. A Ryan spokesman tweeted that it was a coincidence that the announcement came during Clinton’s speech.

Democrats immediately pounced on Ryan’s endorsement, with the Democratic Congressional Campaign Committee sending out a fundraising email to supporters within an hour of the news breaking. DCCC spokeswoman Meredith Kelly said in a statement that Ryan’s support of Trump was “obvious” and “inevitable.”

“House Republicans will be inseparably tied to their toxic frontrunner in November, case closed,” Kelly said.