Democratic presidential candidates have struggled in recent days to define what, exactly, they dislike about President Donald Trump’s foreign policy.

Some have accused Trump of abandoning America’s allies. Others accuse Trump of a “retreat” from America’s leadership role, or values. And others accuse him of acting like a “schoolyard bully.”

These criticisms contradict each other, because they all miss the mark. Indeed, Democrats have no answer to “America First.”

At least some of these criticisms appear to be recycled versions of accusations that Republicans made against President Barack Obama’s foreign policy.

For example, Republicans often accused Obama of retreating from America’s role as the leader of the free world. Obama pulled U.S. troops out of Iraq hastily, leaving a vacuum filled by the so-called “Islamic State.” He also failed to back the Green Revolution in Iran, and let Russia do as it wished in the Crimea.

Obama’s withdrawal was based on a fundamental philosophical shift: the belief that America was not “exceptional,” and that our influence on the world had often been malevolent. The Obama administration developed a new model, which it called “leading from behind.” In practice, it meant allowing multilateral institutions and European allies to determine the direction of international policy — even if the U.S. still did most of the heavy lifting behind the scenes.

In general, that approach was a failure. Obama pushed for war against the Gaddafi regime in Libya, couched — unlike the Iraq War — in the approval of the United Nations and the Arab League. But the war was strategically muddled, and the allies failed — as in Iraq — to provide security and stability in its aftermath. By the time the administration turned its attention to Syria, Obama had embraced a more interventionist doctrine, at least in theory: he did nothing, in practice.

Another Republican criticism of Obama was that he had abandoned America’s allies. Nowhere was that clearer than in Israel, where Obama pursued a deliberate policy of creating distance between his administration and the government of Israeli Prime Minister Benjamin Netanyahu, in the hope of appeasing the Muslim world and enticing the Palestinians to the negotiating table. In fact, Obama’s policy had the opposite effect, encouraging the Palestinians’ radical demands.

Obama also broke promises to U.S. allies in Eastern Europe to follow through with commitments on missile defense — a betrayal that had been foreshadowed during the 2008 campaign, when then-Sen. Barack Obama (D-IL) offered a tepid response to the Russian invasion of Georgia. He was also viewed within the Middle East as having abandoned pro-American regimes during the upheavals of the Arab Spring, and backing the Muslim Brotherhood in Egypt.

Republicans also lamented that Obama had abandoned American values — especially in his obsequious gestures to foreign strongmen. He offered Russian President Vladimir Putin a “reset,” and promised his successor to be more “flexible” on missile defense after the 2012 election. He bowed to the Saudi king and the Japanese emperor, and lectured the Muslim world about America’s failings — what he called “our own darker periods in our history.”

Democrats may have appropriated these Republican attack lines because they remember how effective they were against Obama. But they do not quite work against Trump.

Trump has led decisively, both through military action (against Syria, for example) and diplomacy (for instance, in North Korea). He has strengthened U.S. alliances with Israel and the Arab world at the same time, and has improved ties with the post-communist nations of Eastern Europe.

Where Obama was largely silent on human rights issues, believing perhaps the U.S. had no moral right to criticize others, the Trump administration has been vocal in many cases — even if it could, at times, have been more so. Trump has been reluctant to criticize Russia — but so was Obama, and Trump has been more assertive in countering Russia when American interests have been at stake. (Democrats’ newfound Russophobia is mostly about domestic politics.)

In essence, Democrats’ complaints about Trump’s foreign policy boil down to three or four grievances. They are upset that he has withdrawn the U.S. from international institutions and agreements. They do not like his confrontational approach to Western Europe on issues like financial commitments to NATO. They are upset that he wants to harden the border with Mexico against migrants from Latin America. And, increasingly, they dislike Trump’s pro-Israel stance.

Many of the Democratic candidates have promised to undo these policies. But they all struggle to explain why. After Trump pulled out of the Paris Climate Accords, for example, many supporters of the agreement admitted it was both ineffective and unenforceable.

Moreover, key Democrat constituencies agree with Trump’s approach — especially on trade. The unions have been forced, despite their partisan loyalties, to praise Trump’s policies on China and NAFTA.

It turns out there are not many good rejoinders to “America First” — the idea that the U.S., like every nation, should prioritize its own interests. The phrase itself was taboo, thanks to its association with Charles Lindbergh’s isolationism. But Trump rehabilitated the term, and showed “America First” does not mean “America alone.”

Trump’s foreign policy has been, thus far, remarkably successful. No wonder Democrats are finding it difficult to come up with a clear answer.

Joel B. Pollak is Senior Editor-at-Large at Breitbart News. He is a winner of the 2018 Robert Novak Journalism Alumni Fellowship. He is also the co-author of How Trump Won: The Inside Story of a Revolution, which is available from Regnery. Follow him on Twitter at @joelpollak.