【Farmer’s Wife: Handle with Care! Part 1: Angel Advent】

President Barack Obama on Farmer’s Wife: Handle with Care! Part 1: Angel AdventTuesday laid down perhaps his biggest verbal smackdown of Donald Trump since the famous 2011 White House Correspondents Dinner, though he wasn't smiling as much this time around.

Obama blasted Trump and other Republican leaders who have not rescinded their endorsements of the GOP presidential candidate.

"I think the Republican nominee is unfit to serve as president," Obama said at a press conference alongside Singapore's Prime Minister Lee Hsien Loong. "I said so last week, and he keeps on proving it."

Obama's remarks on Trump start at around the 59 minute mark in the video below.

Obama expressed shock at Trump's continued attacks on the family of slain Muslim United States soldier Humayun Khan, and said the Republican candidate "doesn’t appear to have basic knowledge around critical issues in Europe, in the Middle East, in Asia."

The president then turned his ire toward House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell. He questioned why they still endorse Trump despite having to make multiple statements decrying comments Trump has made.

Both Ryan and McConnell issued statements over the weekend to say they supported the Khan family while Trump tried to play the victim, saying the family had "viciously attacked" him on stage at the Democratic National Convention, where Humayun's father spoke out against Trump's proposal to ban Muslims from entering the U.S.

"The question that they, I think, have to ask themselves, is if you are repeatedly having to say in very strong terms that what [Trump] has said is unacceptable, why are you still endorsing him?" Obama asked. "What does this say about your party, that this is your standard bearer?"

Then Obama drove his argument a little further, making it clear that he didn't just disagree with Trump's policies but that he believed he did not have the experience to run the country.

"There have been Republican presidents with whom I disagreed with but I didn't have a doubt that they could function as president. I think I was right and Mitt Romney and John McCain were wrong on certain policy issues, but I never thought that they couldn’t do the job," Obama said.

"And had they won, I would have been disappointed, but I would have said to all Americans this is our president and I know they’re going to abide by certain norms and rules and common sense, will observe basic decency, will have enough knowledge about economic policy and foreign policy and our constitutional traditions and rule of law that our government will work, and then we’ll compete four years from now to try to win an election.

"But that’s not the situation here. And that's not just my opinion. That's the opinion of many prominent Republicans. There has to come a point at which you say, 'enough.'"

Though the GOP leadership still backs Trump, Representative Richard Hanna became the first sitting Republican representative to back Clinton on Tuesday, also calling the GOP nominee "unfit to serve."

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