Would Trump drive NATO exit? Congress works on roadblocks.

WASHINGTON ― Amid uncertainty over President Donald Trump's intentions toward NATO, Congress is taking bipartisan action to stop him from withdrawing from the alliance.

In recent weeks, lawmakers in both chambers have taken steps to reaffirm its unwavering support for the military alliance and make it tougher for Trump to unilaterally withdraw from NATO ― all to counterbalance the president's sometimes antagonistic rhetoric and, reportedly, his openness to a withdrawal.

The House last week passed a sweeping defense policy bill that would reaffirm strong congressional support for NATO and prohibit the use of U.S. funds to withdraw from the alliance. The Senate is expected to send the bill, the 2020 National Defense Authorization Act, to Trump, who has said he will sign it into into law.

"The NDAA ensures that America not only is a reliable partner in NATO, but that NATO remains the cornerstone for peace and prosperity throughout the world," the author of the language, Rep. Jimmy Panetta, D-Calif., said in a statement last week.

The action is meant to reassure allies as trans-Atlantic ties have been frayed by disputes over defense spending, trade, America's withdrawal from the Iran nuclear deal, and Turkey's invasion of northern Syria as well as its purchase of a Russian air defense system.

House overwhelmingly passed Panetta's language in January, and NATO Secretary General Jens Stoltenberg made a warmly received joint address to Congress in April.

On Dec. 11, the Senate Foreign Relations Committee took a step of its own. Voting unanimously, the committee advanced a bipartisan bill that would require congressional approval before any U.S. withdrawal, in effect closing a loophole in the U.S. Constitution.