On nuclear restraint, Trump’s stance murky

First-strike strategy is difficult policy issue

WASHINGTON—Donald Trump’s ambiguous answer to a debate question on nuclear restraint raised doubts about his understanding of the issue. On the other hand, his words—by design or coincidence—mirror the nub of a policy argument the administration is wrestling with in the final months of Barack Obama’s presidency.

Asked at this week’s debate whether he supports the decades-old U.S. policy of refusing to rule out being the first to use nuclear weapons, Trump at first said, “I would certainly not do first strike.” That would seem to indicate he does not support the current policy of keeping it indefinite. But then he said, “I can’t take anything off the table.” And that would suggest just the opposite: that he would not rule out a nuclear first strike.

It was difficult to tell whether Trump has considered this aspect of nuclear weapons policy. Or some others. During a Republican primary debate he was asked his view on modernizing the three main elements of the U.S. nuclear arsenal, known as the “triad,” and he couldn’t name all three: missiles launched from the air, underground silos and submarines.

In his answer Monday he tossed in a mention of the B-52 bomber, which is part of the airborne leg of the nuclear triad. He correctly said the B-52 is extraordinarily old by weapons standards, and he said this shows the U.S. is “not keeping up” with other nuclear powers. The U.S. actually is planning to build a new-generation bomber and to replace all other elements of its nuclear arsenal.

Questions about the circumstances in which the United States might use a nuclear weapon have resurfaced as Trump opponents have openly expressed fear that he would use them unwisely.

“A man you can bait with a tweet is not a man we can trust with nuclear weapons,” Hillary Clinton said in her speech accepting the Democratic presidential nomination.

Two Democratic lawmakers, Rep. Ted W. Lieu of California and Sen. Edward J. Markey of Massachusetts, said Tuesday they had introduced a bill that would prohibit the president from launching a nuclear first strike without a declaration of war by Congress.

But Thomas Mahnken, president of the Center for Strategic and Budgetary Assessments, said he hopes Obama does not choose to adopt a “no first use” policy.

“Potentially it would be a president in the waning months of his administration seeking to tie the hands of his successor.”