Republican presidential front-runner Donald Trump outlined his "America first" foreign policy platform Wednesday, promising to build up the U.S. military, force allies to invest more in defense and emphasize stability over what he called nation-building overreach.

"After the Cold War our foreign policy veered badly off course," he told a Washington, D.C., crowd just hours after another sizable primary win the previous evening. "As time went on, our foreign policy began to make less and less sense. Logic was replaced with foolishness and arrogance, which led to one foreign policy disaster after another.

"Our foreign policy is a complete and total disaster. No vision. No purpose. No direction. No strategy."

Trump's own outline was billed as a broad overview of his general philosophy on international relations and security, and stayed away from specifics on spending and diplomatic moves. Critics have blasted that lack of detail throughout his campaign, but so far it hasn't seriously hurt him among voters.

One of the few specifics he did offer was in criticism of President Obama's military spending strategy, which he repeatedly tied to the policies of Democratic presidential front-runner Hillary Clinton.

"Our active-duty armed forces have shrunk from 2 million in 1991 to about 1.3 million today," he said. "The Navy has shrunk from over 500 ships to 272 ships during this same period of time. The Air Force is about one-third smaller than 1991. Pilots flying B-52s in combat missions today. These planes are older than virtually everybody in this room."

The solution, he said, is ensuring that the military is "funded beautifully" but also added "we will look for savings and spend our money wisely." That includes not just the Pentagon but also "our trade, immigration and economic policies to make our economy strong again."

Trump also chastised NATO allies for not spending enough on their own defense forces, vowing to make them accept their fair share of the expense and responsibility.

"The countries we are defending must pay for the cost of this defense, and if not, the U.S. must be prepared to let these countries defend themselves," he said. "We have no choice."

At the same time, he criticized Obama and Clinton for undermining foreign faith in American support. He attacked the Iranian nuclear deal as bad for security and humiliating for the country, lowering the United States' reputation in the eyes of countries throughout the Middle East.

Trump promised that after he becomes commander in chief, he will convene a summit with NATO allies and Asian allies to "discuss a rebalancing of financial commitments" and "take a fresh look at how we can adopt new strategies for tackling our common challenges."

Those will include Islamic State fighters, who he promised to destroy.

"I have a simple message for them: Their days are numbered," he said. "I won't tell them where and I won't tell them how. … But they're going to be gone."

Trump went even further on the lack of specifics in that strategy, saying that he'll never reveal troop moments and strategy to the extent Obama has.

"We must as a nation be more unpredictable," he said. "We tell everything. We're sending troops. We tell them. We're sending something else. We have a news conference. We have to be unpredictable. And we have to be unpredictable starting now."

A CNBC poll conducted earlier this month found "foreign policy and terrorism" the second most pressing issue among voters, behind only "the economy and unemployment."

Leo Shane III covers Congress, Veterans Affairs and the White House for Military Times. He can be reached at lshane@militarytimes.com.