WASHINGTON — Donald Trump has trashed German Chancellor Angela Merkel, expressed admiration for Russian President Vladimir Putin and suggested it would be a good idea for Japan and South Korea to obtain nuclear weapons.

Most of what he says has alarmed the traditional foreign policy crowd, but even so there may be a kernel or two of an idea that ought to be explored, others offer.

“He’s made so many statements that reflect little understanding and detail, but even a blind squirrel finds a nut every now and then,” said Christopher Preble, vice president for defense and foreign policy for the libertarian-leaning Cato Institute.

Here’s a review of some of Trump’s proposals.

NUCLEAR WEAPONS

In televised town halls and in interviews, Trump has suggested that Japan and South Korea obtain nuclear weapons as a way to keep North Korea’s nuclear ambitions in check.

“At some point, we have to say, you know, we’re better off if Japan protects itself against this maniac in North Korea, we’re better off, frankly, if South Korea is going to protect itself,” Trump said during a CNN town hall. “Now, wouldn’t you rather in a certain sense have Japan have nuclear weapons when North Korea has nuclear weapons?”

Trump is correct in that the world has changed dramatically in the last few decades and for the United States not to review its relationships and policies with its allies “would be utterly absurd,” Preble said.

But, he added, the idea of reducing the threat of nuclear weapons by adding more nations to the nuclear club is unwise and unrealistic.

“I think it’s not a great idea, but ultimately it comes down to the Japanese and the South Koreans,” he said. “In the case of Japan, there are strong pacifist restraints in Japan. And Japan has a particular aversion to nuclear weapons. You can check history for the reason why.”

Michael O’Hanlon, co-director of the Center for 21st Century Security and Intelligence at the Brookings Institution, a center-left Washington research center, doesn’t embrace Trump’s idea of a nuclear Japan or South Korea, but added that “I think they would be responsible” if they had the bomb.

But he said the fear would be what’s next: He worries about Taiwan and Saudi Arabia having nuclear weapons.

President Obama on Friday was more direct in his comments after a nuclear security summit in Washington. Trump’s remarks, he said, show he “doesn’t know much about foreign policy, or nuclear policy or the Korean peninsula, or the world in general.”

He said Trump’s remarks came up on the sidelines in talks with leaders at the summit.

“Even in those countries that are used to a carnival atmosphere in their own politics want sobriety and clarity when it comes to U.S. elections,” Obama said.

White House deputy national security adviser Ben Rhodes joined a chorus of foreign policy experts and lawmakers who believe the United States giving Japan and South Korea the nod to go nuclear is a bad idea.

“The entire premise of American foreign policy as it relates to nuclear weapons for the last 70 years,” he said, “has been focused on preventing the proliferation of nuclear weapons to additional states.”

DEFEATING THE ISLAMIC STATE

Trump has proposed a number of ideas for confronting the Islamic State, from bombing it to confiscating its oil to assembling a force composed of U.S. Middle East allies to invade the territory it controls. In August, he said the U.S. may have to send in its own ground forces, saying, “I would listen to the generals, but I’m hearing numbers of 20,000-30,000.”

Shadi Hamid, a senior fellow in Brookings’ Center for Middle East Policy, said Trump’s proposals aren’t likely to be acceptable.

“Theoretically, you could bomb Mosul, but America doesn’t do that anymore,” he said. “It would kill a lot of civilians and put us in a position of committing war crimes. There are countries that do do that – Russia and the Syrian regime.”

But Hamid added that “as a country, we should be open to a national conversation on whether ground troops are necessary.”

O’Hanlon questioned Trump’s grasp of Islam’s internecine struggles in the region, which pit Sunni Muslim powerhouse Saudi Arabia against its Shiite archrival Iran. He said Trump’s vision for eliminating the Islamic State threat doesn’t focus enough on the political elements that helped give the terrorist group birth.

“You have to understand ISIS in terms of its origin and the Middle East – which is bad for Trump,” O’Hanlon said. “You need to have a feel for that. The politics behind it are crucial. If you don’t understand that, you’re back at square one.”

NATO

Trump has criticized NATO, the military alliance that includes the U.S., Canada and much of Europe as “obsolete” and said it needs to focus on terrorism: “When NATO was formed many decades ago we were a different country. There was a different threat,” he said in an interview with The New York Times, referring to the Soviet Union, which he argued was “certainly much more powerful than even today’s Russia.”

As part of that criticism, he’s seized on a perennial NATO critique that most member countries do not spend at least 2 percent of their gross domestic product on defense, as required by the alliance’s guidelines.

Analysts agree that’s a valid criticism, but they note that of NATO’s members, only the United States is a world power.

“There’s a small kernel of truth there,” said Stephen Long, an international security expert at the University of Richmond, “but he’s blown it way out of proportion.”

“The U.S. is projecting power around the world in multiple theaters, simultaneously; it’s not all directed at Europe,” Long said. “You look at the small members of NATO, they don’t have the capacity to project military power abroad and it should come as no surprise to anyone that the U.S. is spending more.”

Still, Trump’s criticism echoes that of the Obama administration, which has sought, mostly unsuccessfully, to persuade NATO member countries to increase their defense spending.

Obama in 2014 told NATO members that “every ally needs to carry their share and truly invest in the capabilities of the alliance that are needed for the future.”

He used sharper language in a recent interview with The Atlantic, saying that some European countries are “free riders.”

But for Trump to argue that the imbalance means NATO is not relevant is “irresponsible,” Long said.

“If anything, NATO is more relevant than it’s been since end of the Cold War, with (Russian President Vladimir) Putin behaving aggressively,” he said. “The idea that somehow NATO is irrelevant because the cost sharing is not perfectly aligned is absurd.”

Indeed, argues Michael J. Geary, a global fellow at the Woodrow Wilson International Center for Scholars in Washington and professor of European Studies at Maastricht University in the Netherlands, NATO may be more relevant now than ever.

“Clearly, many European NATO members would be highly anxious, if not downright worried, about Trump’s comments,” Geary said. “NATO has become increasingly necessary as a bulwark against Russia in the clear absence of any EU foreign military policy.”

MUSLIM BAN

Trump called for a “total and complete shutdown of Muslims entering the United States until our country’s representatives can figure out what is going on” after last year’s terrorist attacks in Paris and San Bernardino, Calif. He later clarified the ban to include only non-American Muslims.

Critics decried the proposal as unconstitutional _ and simply unworkable, noting that religion is not included on travel documents. Trump suggested border agents would ask arrivals: “Are you Muslim?'”

The plan drew sharp condemnation from Trump’s then-presidential rivals, including former Gov. Jeb Bush of Florida, who said the move would “push the Muslim world, the Arab world, away from us at a time when we need to re-engage with them to be able to create a strategy to destroy ISIS.”

Pressed on that, Trump suggested this week that “maybe they’ll be more disposed to fight ISIS. Maybe they’ll say, ‘We want to come back into America; we’ve got to solve this problem.’ He added, “What are we going to do, just sit back and say we want to be nice to everybody? We can’t be so nice.”

Analysts say a religion-based ban would likely violate the First Amendment’s religious freedom clause, along with the due process clause in the Fifth Amendment.

“I doubt that courts would read that law to authorize the president to remove non-citizens based on religion,” Ilya Shapiro, a senior fellow in constitutional studies at the libertarian Cato Institute, told PolitiFact.