Hillary Clinton just delivered one of her strongest arguments yet against Donald Trump

Hillary Clinton is looking ahead to the general election and training her fire on Donald Trump.

She roasted her likely opponent in a lengthy speech on foreign policy on Thursday, emphasizing her experience and saying that electing Trump to the presidency would be a "historic mistake."

Clinton's speech got rave reviews from foreign-policy and political analysts, as well as from pundits on TV networks after it aired. CNN host Fareed Zakaria called it "the best speech she has ever made."

The address covered a lot of ground. She hit Trump on his proposal to build a wall along the US border with Mexico, his criticism of the Iran nuclear deal, his comments on US alliances and nuclear proliferation, his calls to bar Muslim immigrants from entering the US, and his readiness as commander in chief.

"It's very challenging for Hillary to make a good foreign-policy argument against Trump," Ian Bremmer, a geopolitical expert and president of the Eurasia Group, told Business Insider via email, calling the speech "very solid."

"Most of what he's arguing for is completely implausible (nukes for Japan; a trade war with China); some is unconstitutional (a Muslim ban, sending back immigrants). But he's not in any way being punished for his policy agenda," Bremmer continued.

Trump, the presumptive Republican nominee for president, has suggested that South Korea and Japan might need to obtain nuclear weapons, said he would restrict imports from China, and threatened to deport millions of immigrants living in the US illegally.

"He's promising to be everything that the establishment hasn't been - and to be fair, on that limited count, he's certainly delivering," Bremmer said.

Still, Clinton has been slipping in primary polls in California, and Trump continues to see a groundswell of support among Republicans. While Clinton was delivering her speech in California, House Speaker Paul Ryan endorsed Trump for president.

Clinton "has plenty of intellectual points she can score," Bremmer said. "I'm certain the foreign-policy establishment found much to like. Lord knows they detest Trump - and they aren't getting on board the way the Republican leadership is.. ... But that isn't going to swing the election."

Whether or not this speech will alone tilt the balance of election in November, it's one of the most comprehensive looks we've gotten yet of what Clinton will bring to her general-election campaign if, as expected, she secures the Democratic nomination for president.

Here are some of the key points she made against Trump in the speech:

• On his proposal for a wall along the US border with Mexico to keep out undocumented immigrants: "We are not a country that cowers behind walls. We lead with purpose, and we prevail." And: "We're lucky to have two friendly neighbors on our land borders. Why would he want to make one of them an enemy?"
• On his criticism of the Iran nuclear deal: "Donald Trump doesn't know the first thing about Iran or its nuclear program. Ask him. It'll become clear very quickly." And: "There's no risk of people losing their lives if you blow up a golf-course deal. But it doesn't work like that in world affairs."
• On his suggestion that US allies don't contribute enough to their own defense: "Yes, our friends need to contribute their fair share. I made that point long before Donald Trump came onto the scene."
• On his statements about Muslims: "Through all his loose talk, there's one constant theme: Demonizing Muslims and playing right into the hands of ISIS."
• On his vague plans to combat the terrorist group ISIS: "A Trump presidency would embolden ISIS. We cannot take that risk."
• On his readiness as commander in chief: "Imagine Donald Trump sitting in the Situation Room, making life-or-death decisions on behalf of the United States. Imagine if he had not just his Twitter account at his disposal when he's angry, but America's entire arsenal. ... Do we want him making those calls - someone thin-skinned and quick to anger, who lashes out at the smallest criticism?"
• On his foreign policy experience: "He says he has foreign-policy experience because he ran the Miss Universe pageant in Russia."

But Clinton didn't spend all her time attacking Trump - she also outlined her own credentials.

"I have some experience with the tough calls and the hard work of statecraft," she said. "I wrestled with the Chinese over a climate deal in Copenhagen, brokered a ceasefire between Israel and Hamas, negotiated the reduction of nuclear weapons with Russia, twisted arms to bring the world together in global sanctions against Iran, and stood up for the rights of women, religious minorities and LGBT people around the world."

She also hit back against Trump's "America-first" strategy.

"I believe in strong alliances; clarity in dealing with our rivals; and a rock-solid commitment to the values that have always made America great," Clinton said.

She made the case for American power around the world.

"I believe with all my heart that America is an exceptional country - that we're still, in Lincoln's words, the last, best hope of earth. We are not a country that cowers behind walls. We lead with purpose, and we prevail." she said.

And she warned about what she thinks might happen if the US embraces Trump's more isolationist worldview.

"If America doesn't lead, we leave a vacuum - and that will either cause chaos, or other countries will rush in to fill the void.  Then they'll be the ones making the decisions about your lives and jobs and safety - and trust me, the choices they make will not be to our benefit," Clinton said.

Here's how some other experts reacted to the speech on Twitter: