Donald Trump will kick off a series of speeches on Wednesday that aim to recast the real-estate mogul as a more sober and serious presidential candidate than he’s perceived by many Americans and foreign allies. It won’t be easy.

Trump’s critics include foreign policy specialists across the ideological spectrum who view the Republican front-runner as erratic and misguided, and say he’s pushing ideas that endanger U.S. interests. He has faced criticism for making campaign promises such as banning Muslims from entering the U.S., forcing Mexico to pay for a border wall between the two nations and, as he suggested Monday at a rally in West Chester, Pennsylvania, making Gulf states pay for a “safe zone” in Syria. His freewheeling temperament has also been a target.

“The main takeaway for me is an unpredictability. That would be the most worrisome issue among our friends and allies around the world-what Trump says today may not be what he says tomorrow. And he does not seem to have much compunction about changing his views,” said Richard LeBaron, a senior fellow at the Atlantic Council and longtime diplomat who served as U.S. ambassador to Kuwait under President George W. Bush. “It’s very rarely a useful tool in foreign policy. … It leads to misperceptions and it leads to miscalculations by other countries in how they react to the United States.”

It remains to be seen whether Trump will tailor his speech on Wednesday in Washington to an audience of foreign policy elites or the masses of voters he hopes will make him president. If it’s the former, he has a steep hill to climb in gaining favor.

A rollout last month of his foreign policy team, led by U.S. Senator Jeff Sessions, did little to quell doubts. Michael Hayden, a former Central Intelligence Agency director under George W. Bush and Barack Obama, told Politico’s Off Message podcast he’d trust Democratic front-runner Hillary Clinton over the “incoherent” Trump on national security, even though he leans Republican. Trump has also faced fire from neoconservative hawks in his party, such as former rivals Marco Rubio, a Florida senator, and Lindsey Graham, a South Carolina senator, for proposing to reconsider U.S. participation in NATO and to bring back waterboarding.

Despite the criticism, Trump routinely outshines his Republican competitors among voters in the primary on questions of trust in handling terrorism and national security, indicating that his brash rhetoric and hawkish isolationism has caught on with the party base. In his telling, America’s enemies must be crushed by all means necessary (even torture), and allies like Saudi Arabia need to pay up to show their appreciation of the U.S. protections they enjoy.

“A strong element of Trump’s foreign policy is just a massive fear of the rest of the world,” said Daniel Drezner, a professor of international politics at Tufts University. “To any kind of foreign threat, his response is just to wall off the United States … literally and figuratively. He does believe we can use the threat of U.S. economic power to somehow rewrite the rules.”

Trump won support among GOP voters for staking out a position on banning Muslims from entering the U.S. He announced his position in December after terrorist attacks in Paris and San Bernardino, California, and enjoyed the support of majorities of Republican voters in primary and caucus states, according to exit polls. The loudest applause line in his stump speech is his call to build a wall on the southern border and and exert economic power to re-negotiate trade pacts with China and Mexico so they better serve American workers.

The U.S. must spare no effort to crush anyone who would threaten it-“we’re gonna knock out ISIS,” Trump said Monday during a rally in West Chester, Pennsylvania-and withdraw from commitments to Japan and South Korea aimed at keeping China and North Korea in check, even if it means the two nations build nuclear weapons.

“It combines militarism with isolationism,” said Peter Beinart, a foreign policy commentator and professor at the City University of New York. “It’s a very zero-sum idea of what is best for America-our enemies should be attacked ferociously but with no real interest in the context which the enemies [arise], no interest in trying to shape the societies. There’s a zero-sum mentality that we’re getting screwed by our trading partners and we need to be tougher on them.”

Some foreign allies have expressed dismay at many of Trump’s proposals.

“There have been episodes in human history, unfortunately, where these expressions of this strident rhetoric have only led to very ominous situations in the history of humanity,” Mexican President Enrique Peña Nieto told the Excelsior newspaper in regard to Trump’s assurances that his country would pay for a border wall. “That’s how Mussolini got in, that’s how Hitler got in, they took advantage of a situation, a problem perhaps, which humanity was going through at the time, after an economic crisis.”

Trump’s rejection of military intervention in pursuit of democratization in Libya and Syria also puts him crosswise with many neoconservative policy advisers. His emphatic opposition to the Iran nuclear deal demonstrates a deep skepticism of diplomacy, unlike former secretary of state Clinton, who puts a premium on “soft power,” or coercive diplomacy. Last month on MSNBC, Trump described himself as his chief foreign policy adviser, “because I have a very good brain.”

The address Wednesday comes amid a shakeup at the highest levels of Trump’s operation, including the addition of campaign veterans Paul Manafort and Rick Wiley in top positions.

“I am honored to be invited to speak at an organization founded by former President Richard Nixon, and look forward to sharing my views on the many serious foreign policy issues facing our country and our allies around the world,” Trump said in a statement. “Trade, immigration and security policies are critical concerns of all Americans, and we must develop a clear, consistent long-term foreign policy for making America safe and prosperous.”

Whether Trump will seek to mitigate foreign policy specialists’ misgivings will be closely watched. His challenge is the large gulf between the world-weary GOP base and many pro-interventionist elites.

Another question is how Trump will contrast himself with Clinton, who as America’s former top diplomat and former senator from New York would be one of the most experienced foreign policy figures ever to be elected president.

“Trump could try to make the case that Hillary Clinton is more hawkish and war prone than Trump would be,” said Drezner, who posited that Trump could cite Clinton’s vote to authorize the Iraq invasion and her support for regime change in Libya. “But it’s going to be very easy for Clinton to push back on that,” Drezner added, arguing that she could paint him as dangerous by pointing to rhetoric suggesting he’s willing to bomb terrorists’ families or let Japan and South Korea build nuclear weapons.

LeBaron noted that foreign policy traditionally isn’t a major electoral concern for voters, and that positions taken by presidential candidates on international affairs often don’t reflect their actions after taking office.

To the extent that it matters, foreign policy is shaping up to be a vulnerability for Trump in a match-up against Clinton, according to a recent George Washington University Battleground Poll. The survey found even though a generic GOP candidate has an advantage of 48 to 44 percent over Democrats on foreign affairs, Clinton leads Trump by a margin of 60 to 33 percent in that category among voters nationally.

“The essential thing she can say is that you cannot trust Donald Trump with the nuclear codes,” Drezner said. “If Clinton was smart, she would also paint Trump as someone who is so short-tempered and sensitive that you don’t know what he’ll do-someone who’ll fly off the handle.”

(c) 2016, Bloomberg · Sahil Kapur