CAPITOL HILL – If the U.S. opts to develop low-yield nuclear missiles, expect the Navy to deploy these weapons as part of the nation’s undersea nuclear deterrent, the commander of U.S. Strategic Command told lawmakers Thursday.

If developed, the U.S. low-yield nuclear weapons would fall within limits set by the New START nuclear arms treaty, Air Force Gen. John Hyten, commander of U.S. Strategic Command, told the House Armed Services strategic forces subcommittee. New START, signed in 2010 by the U.S. and the Russian Federation, caps the number of nuclear warheads each nation deploys.

“We’ll actually remove big weapons from the submarines and put small ones in,” Hyten said. “We’re going to have still the same number weapons, they just going to give us a smaller yield. But we think that smaller yield actually gives us a better chance to deter our primary adversary.”

Pentagon leaders and members of Congress worry Russia, China and others already are developing low-yield nuclear weapons in an attempt to gain an advantage over the U.S. or allied nations protected by the U.S. nuclear umbrella, said the subcommittee’s ranking member, Rep. Michael Turner (R-Ohio).

“There is a concern that we might not retaliate, because if all of our weapons are such a large size, that we would be deterred because we’d be seen as escalating to their escalate,” Turner said.

However, not all lawmakers agree that low-yield nuclear weapons dramatically increase the ability of the nation’s nuclear triad to deter adversaries. Their worry is developing low-yield nuclear weapons will result in a low-yield nuclear arms race.

“I continue to be unconvinced of the value of low-yield weapons,” Rep. Susan Davis (D-Calif.) said.

Several of Davis’ colleagues share her skepticism, including HASC chair Rep. Adam Smith (D-Wash.). Smith is a frequent critic of the low-yield nuclear weapons plan. In September, he was among a group of lawmakers from the House and Senate who sought to prohibit the development of low yield nuclear weapons for submarines.

“We should not fund President Trump’s request for new low-yield nuclear weapons. His proposal dangerously lowers the threshold to nuclear use and siphons money away from genuine military readiness needs,” Smith said at the time. “We already have a nuclear deterrent that is more than adequate to achieve our national security goals. Funding new, low-yield weapons would only draw us further into an unnecessary nuclear arms race and increase the risks of miscalculation.”

Meanwhile, as the Pentagon waits for approval to develop low-yield nuclear weapons, military leaders are also developing hypersonic weapons. However, if created, the Columbia-class SSBN submarines will not carry hypersonics.

“There is no plan to put a conventional weapon on an SSBN,” said Vice Adm. Johnny Wolfe, the Navy’s director of Strategic Systems Programs.

Wolfe did leave the door open for deploying hypersonic missiles aboard a proposed Columbia-class follow-on submarine that would not be designed to carry nuclear weapons. The Navy is considering shifting Columbia-class production into a guided missile submarine program (SSGN) as the final of the 12 planned Columbia-class boomers are built.

The Navy’s Fiscal Year 2020 budget request asks for about $593 million to pay for additional hypersonic flight testing, booster development and evaluating how to integrate hypersonic missiles into various Navy platforms, Wolfe said. He only offered to give lawmakers a timeline for flight testing in a classified hearing.

“The whole goal of these weapons is to not use them,” Hyten said. “The key is by being ready, by being obviously ready, and communicating that with the adversary, we will not cross that line, and we will not have to use them. If we’re not ready, that’s why we’re concerned somebody will cross that line.”