With Democrats acting as a united front, on July 12 the House of Representatives voted to kill a new nuclear weapon that President Trump would have been able to launch next year—a lower-yield and more usable weapon that would increase the risk of nuclear war. This House vote, the first to stop a new atom bomb in over a decade, sends a powerful message to candidates for the White House in 2020: your base does not want Trump to have new nukes.

This was a tremendous Democratic victory against a determined Trump administration and Republican House caucus. The administration had proposed this new weapon as part of the February 2018 Nuclear Posture Review, with full support of the Pentagon and then-Defense Secretary James Mattis. The GOP-controlled Congress approved the warhead last year, and it was on a fast track for deployment in 2020.

The July 12 vote pumped the brakes on these ill-conceived plans, a success that would not have been possible before the 2018 elections that flipped the House and gave Rep. Adam Smith, D-Wash., a powerful new perch as the chair of the House Armed Services Committee. "It makes no sense for us to build low-yield nuclear weapons," Smith said at the Ploughshares Fund policy conference in November. "It brings us no advantage and it is dangerously escalating. It just begins a new nuclear arms race with people just building nuclear weapons all across the board in a way that I think places us at greater danger."

But even before the election, Ploughshares Fund and our allies were building opposition to Trump’s low-yield blooper. For example, former Secretary of Defense Bill Perry and I teamed up last spring to write an op-ed that argued that there exists “no need for such weapons, and building them would make us less safe. These so-called ‘low-yield’ nuclear weapons are a gateway to a nuclear catastrophe.”

Ploughshares Fund then worked with the Union of Concerned Scientists to produce a letter to Congress opposing the new weapon. The letter, signed by more than 30 experts (including Bill Perry, former Secretary of State George P. Shultz, former Gov. Jerry Brown, former chairman of Strategic Command Gen. James Cartwright, former Sen. Richard Lugar, and Ben Rhodes, President Obama’s Deputy National Security Advisor), was delivered to all members of Congress.

We also had the support of key allies who introduced stand-alone legislation to prohibit the new warhead. In September 2018, Rep. Ted Lieu, D-Calif., Sen. Ed Markey, D-Mass., Rep. Smith, and others introduced the Hold the LYNE (Low-Yield Nuclear Explosive) Act, which became an effective focus of opposition to the program.

To its credit, the House defense authorization bill also challenges other misguided Trumpian nuclear policies. For example:

∗ It requires an independent study on No First Use, that is, declaring that the United States would only use nuclear weapons to deter an atomic attack and never to start a nuclear war.

∗ It cuts $103 million from the new Intercontinental Ballistic Missile (ICBM), a dangerous part of the arsenal that only increases the risk of blundering into war.

∗ It supports the extension of the 2010 New START treaty, the only current bilateral agreement limiting Russian nukes, which Trump’s national security advisor John Bolton has called “unilateral disarmament” and has vowed to destroy.

But the fight is not over. The Senate authorization bill does not include these wise provisions. Now we go to conference, where the two bills need to be brought into agreement. As ranking member on the Senate Armed Services Committee, Sen. Jack Reed, D-Rhode Island, will play a key role here. And, if we make it that far, the final bill still needs to be signed by President Trump, who should be reluctant to veto a bill that gives him at least $733 billion for defense.

Regardless of what happens next, House Democrats have made it crystal clear how they feel about Trump and nuclear weapons: no new nukes, no first use, and more arms control. Presidential candidates for 2020, are you listening?