Within minutes of being sworn in as America’s 45th president, Donald Trump delivered an inaugural address marked by a warning to foreign leaders that “from this day forward it’s going to be only America first.”

That nationalist declaration, including a blunt assertion that “every decision on trade, on taxes, on immigration, on foreign affairs will be made to benefit American workers,” led to immediate fears among internationalists at home and abroad that the new president would begin to pull back from traditional American roles and commitments abroad.

One year later, the actual results are far murkier than those blunt words suggested.

In many ways, the fears of a broad American pullback have proved overblown, at least for now. Despite periodic complaints by Mr. Trump that the U.S. is doing too much global security work that should be left to others, Pentagon data show that the deployment of American troops overseas actually has gone up rather than down over the past year. Troop levels are up in Afghanistan, Iraq and Japan, among other places.

In addition, the Trump administration was the first in years to deploy three carrier battle groups to the Pacific, as part of the effort to warn North Korean leader Kim Jong Un to pull back from his nuclear and missile programs. Mr. Trump also has, with some apparent reluctance, reiterated American support for Article 5 of the North Atlantic Treaty Organization charter committing the U.S. to defend its European allies if they are attacked.