Speaking at the Ohio Democrats’ annual dinner in Columbus on Thursday night, President Obama blasted Republicans for nurturing the sort of extreme thinking that led to Donald Trump’s political rise.

While Obama aimed a few of his swipes at Trump, he directed most of his criticism toward GOP officials who have only recently disavowed their party’s presidential nominee. Frequently, he referred indirectly to Sen. Rob Portman (R-Ohio), who is running for reelection and holds a significant lead over former governor Ted Strickland (D).

“But so the problem is not that all Republicans think the way this guy does. The problem is, is that they’ve been riding this tiger for a long time,” Obama said, referring to those who questioned whether he was born in the United States, those who called him “the antichrist” and subscribers to other conspiracy theories. “They’ve been feeding their base all kinds of crazy for years, primarily for political expedience.”

“People like Ted’s opponent, they just stood by while this happened,” Obama said, referring to Portman. "And Donald Trump, as he’s prone to do, he didn’t build the building himself, but he just slapped his name on it and took credit for it."

“This is in the swamp of crazy that has been fed over and over and over and over again,” Obama said to applause. “So the point is, if your only agenda is either negative — negative is a euphemism, crazy — based on lies, based on hoaxes, this is the nominee you get. You make him possible."

Although Portman withdrew his endorsement for Trump after a 2005 videotape surfaced last week in which Trump made crude remarks about sexually assaulting women, Obama argued that he has more respect for those who actually supported the New York real estate developer “than the people who knew better and stood silently by because it was politically expedient.”

“They know better, a lot of these folks who ran, and they didn’t say anything," Obama said. "And so they don’t get credit for, at the very last minute, when finally the guy they nominated and they endorsed and they supported is caught on tape saying things that no decent person would even think, much less say, much less brag about, much less laugh about or joke about, much less act on. You can’t wait until that finally happens and then say, ‘That’s too much, that’s enough,’ and think that somehow you are showing any kind of leadership and deserve to be elected to the United States Senate. You don’t get points for that.”

At times his remarks appeared aimed at moderate Republicans and GOP-leaning independents, suggesting that elected Republican officials had lost their moral compass.

“And if your only organizing principle has been to block progress and block what we've tried to do to help the American people every step of the way, so you're not even consistent anymore — you claim the mantle of the party of family values, and this is the guy you nominate? And stand by, and endorse, and campaign with until, finally, at the 11th hour you withdraw your nomination? You don't get credit for that,” he said. “You're the party that is tough on foreign policy and opposes Russia — and then you nominate this guy, whose role model is Vladimir Putin, the former head of the KGB? I’m sorry, what happened?”

Rather than delivering an extended pitch for the Democrats' presidential nominee, Obama quipped that members of the audience should look up the video of Michelle Obama’s speech in New Hampshire on Thursday, in which she lambasted the GOP nominee for failing to respect women. The first lady said the multiple allegations of sexual misconduct by Trump have “shaken me to my core.”

"If you want to hear the best case for Hillary Clinton, if you want to hear the very real stakes in this election, I would advise you to link up to Michelle’s speech from earlier today in New Hampshire," he said. “She was pretty good."