House Speaker Paul D. Ryan, R-Wis., ended a monthlong holdout of formally backing his party’s presumptive presidential nominee: Donald Trump.

On Thursday, he penned a guest column for his hometown newspaper in which he trumpeted the controversial real-estate mogul as someone who could support the speaker’s conservative agenda.

“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. It’s not just a choice of two people, but of two visions for America,” Ryan wrote, citing the “bold” policy agenda that he will begin rolling out next week and contrasting that with Democratic front-runner Hillary Clinton. “Donald Trump can help us make it a reality.”

Ryan, who four weeks ago declared he was “not there yet” and questioned whether Trump was even conservative, became the last senior Republican congressional leader to back the controversial businessman’s candidacy. While the speaker did not use the word “endorse”, his column left no doubt where he stood after speaking “at great length” with Trump since he initially declared his hesitation with the candidacy.

Through these conversations, I feel confident he 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.

Initially, the speaker, who likes to call himself a “policy guy” and a “movement conservative,” did not agree with Trump’s positions on key policy planks of mainstream Republicans of the past 40 years, including a free trade agenda and the effort to rein in federal spending on entitlements. Those issues were the hallmark of Ryan’s early congressional career and Trump stands squarely against them.

Additionally, Trump’s proposals to ban all Muslim travel into the United States and his campaign’s tenor in terms of comments regarding minorities, women and the disabled gave Ryan pause.

Those concerns appear to remain, and Ryan vowed to speak out against the presidential candidate if he crosses lines again.

“It’s no secret that he and I have our differences. 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,” he wrote.