Donald Trump in May. (Joe Raedle/Getty Images)

If a presidential convention is a reflection of the nominee, then the first day’s festivities in Cleveland tell us quite a bit about Donald Trump. At least, they confirm two of his glaring weaknesses.

First, the Trump team finds it virtually impossible to withstand or even ignore criticism. Campaign Manager Paul Manafort started things off by kicking the Bush family in the shins for not showing up. “Certainly the Bush family, while we would have liked to have had them, they’re part of the past,” Manafort, whose career goes back to the 1990s, said this morning. “We’re dealing with the future.” Then he attacked popular Ohio Gov. John Kasich for not showing up. Manafort declared, “We think that was a wrong decision.” He then dubbed Kasich’s opting to stay away “embarrassing.” I suppose a great number of Republicans not in attendance — Sens. Kelly Ayotte (R-N.H.) and Mark Kirk (R-Ill.) and New Mexico Gov. Susana Martinez — and therefore relegated to the “past,” in Manafort’s mind. So, no, there is no presidential Trump. There is no time he can pivot away from attacking fellow Republicans. His thin skin, coupled with his narcissistic assurance that he is the only smart one in every room, make it impossible for him to tolerate criticism, even neutrality. Like his idol Vladimir Putin, Trump does not fancy dissent.

The bigger problem for the day and evening, however, is substantive. The “Make America Safe” again theme of the night is especially problematic in a party where the most consistent anti-Trump voices have been foreign policy conservatives. Trump is reportedly now abandoning, perhaps, his Muslim ban after months and months of defending it. One wonders if the rest of his agenda — pulling back on NATO, allowing the spread of nuclear weapons in Asia and to countries such as Saudia Arabia, coziness with Russia, contempt for human rights, etc. — will survive the night. The gap between what Trump has said and what foreign policy hawks believe is vast.

A Senate staffer for a hawkish Republican observes: “Republicans who talk about security but saddle up with Trump have some explaining/soul-searching to do.”

One of those foreign policy conservatives, Sen. Tom Cotton (R-Ark.), an advocate of expanding our footprint in the war against the Islamic State, will speak tonight. He certainly can criticize Hillary Clinton for the Obama administration’s foreign policy weaknesses, but on what basis?

Clinton, for example, wanted to intervene early in Syria as Cotton did; Trump has decided the Syria-Russia team is on our side.

Cotton, who fought in Iraq, surely doesn’t believe, as Trump does, that President George W. Bush lied or that the war was a mistake. Clinton, of course, voted for the war.

Cotton, as well as the hawkish Sen. Joni Ernst (R-Iowa), also have a problem if they criticize Clinton’s reset on Russia. Cotton favors supplying defensive arms to Ukraine and taking a tough line with Putin. My colleague Josh Rogin reports that “the Trump campaign worked behind the scenes last week to make sure the new Republican platform won’t call for giving weapons to Ukraine to fight Russian and rebel forces, contradicting the view of almost all Republican foreign policy leaders in Washington.” Of course, Trump’s campaign is littered with pro-Russian voices. Given Trump’s refusal to release his taxes, we don’t know if he has financial interests in Russia (or in any other problematic nation).

Cotton and Ernst will tiptoe around their vast differences with Trump on policy. They personally are not going defend lifelong beliefs about American leadership. One does have to wonder, however, why they would sublimate their own concerns about national security to back someone so temperamentally unfit to serve as commander in chief and so at odds with their own views.

That gulf between traditional, conservative hawks and Trump will remain. Voters who care about restoring our prestige and influence internationally have serious, substantive disagreements with Trump (in addition to their legitimate concerns about his ignorance and erratic temperament) that will persist. This is Trump’s party now, not Cotton’s or Ernst’s.