To assess President Donald Trump's performance at the G-20 Summit, it is worth remembering two things.

First, for years, Republican foreign policy commentators blasted Barack Obama's "leading from behind" foreign policy strategy as an abdication of U.S. leadership and an abandonment of U.S. allies. A specific criticism was the notion that the Obama administration had done little while Russian President Vladimir Putin had intervened in Ukraine and Syria. A deeper criticism was that Obama seemed reactive to world events. Rather than setting the global agenda, Obama was often criticized for being a prisoner of other people's agendas.

The second thing is that, two months ago, two key Trump White House staff members wrote an extraordinary op-ed in the Wall Street Journal promising that Trump's strategy of "America First" would not mean "America Alone." National security adviser H.R. McMaster and chief economic adviser Gary Cohn were quite explicit on this point.

"America First does not mean America alone. It is a commitment to protecting and advancing our vital interests while also fostering cooperation and strengthening relationships with our allies and partners."

So did last week's G20 summit bear out McMaster and Cohn's claim? No. No, it does not.

In many ways, this cake was baked even before the summit started. The European Union and Japan responded to Trump's protectionist instincts by announcing an agreement on a trade deal. As The Washington Post's Ana Swanson reported:

"Leaders from Japan and the European Union on Thursday announced their agreement on the broad strokes of a trade deal that will cover nearly 30 percent of the global economy, 10 percent of the world's population and 40 percent of global trade.

"... the announcement appeared to be a calculated rebuke of both the United States, which has spurned global trade agreements in favor of more protectionist policies under President Trump, and Britain, which voted to leave the European Union last year."

For all of Trump's happy talk in recent months about China pressuring North Korea, last week's ICBM launch led to a coordinated statement — from China and Russia. As DD Wu at The Diplomat noted:

"What is noteworthy this time is that the July 4 joint statement is actually the first such statement issued under the name of both Foreign Ministries in ten years. The statement's prompt timing as well as the signing parties demonstrates the highest-level consensus and determination between both countries. Given that Russia and China are both the permanent members of the United Nations Security Council, the joint statement implies a strong alliance between the big two on the issue."

So for all the talk about a successful Trump-Xi Mar-a-Lago Summit, it would appear that China coordinated much more with Russia on North Korea.

Finally, the United States was pretty marginalized at the G-20 summit itself.

In the end, they all signed a communique, one that singled out the Trump administration's opposition to the Paris climate change accord.

So, at best, the rest of the G-20 shrugged at Trump's discordant policy positions. At worst, they refused to follow him on any major issue.

Trump's nationalist advisers are apparently giddy about the trip, believing that Trump's Warsaw speech combined with his bilateral meetings in Hamburg made him look presidential. In actuality, his Warsaw speech was a mixed bag. As for his bilateral with, say, Putin, the deliverables are dubious. On the plus side, a cease-fire in Syria appears to be holding. On the down side, Trump's proposed cyber-cooperation with Russia drew widespread mockery from experts and Republican politicians. The criticism was so fierce that Trump managed to contradict himself on Twitter in a single day.

Perhaps the biggest summit fail was the Trump's lack of any agenda-setting power. While Trump had his meetings, ties between other countries (the EU and Japan, Russia and China; the EU and China) seemed to deepen far more.

So, to sum up: No other G-20 member agreed with the United States on the two key issues at the summit, climate change and trade. Trump's most high-profile bilateral meeting proved to be a political embarrassment for the administration. And the rest of the world is growing inured to Trump's America First strategy.

Maybe, just maybe, America First does mean America alone.

Drezner is a professor of international politics at the Fletcher School of Law and Diplomacy at Tufts University.