In reviewing the nation’s nuclear deterrent posture, President Joe Biden’s national security team will closely scrutinize the Air Force’s Long-Range Standoff Weapon (LRSO) program, which is a modernized nuclear-armed, air-launched cruise missile. Critics contend that the weapon may be destabilizing, but delaying or canceling the program would be a huge mistake.

The LRSO—along with gravity bombs—form the “air leg” of the nuclear triad. Each leg of the triad delivers unique and complementary capabilities that together have served to prevent nuclear war for the last seventy-five years. Since our adversaries’ nuclear arsenals pose an existential threat to the United States, it is critical to ensure all elements of the triad remain viable in the future.

The Air Force is set to retire its current cruise missile in 2030, at which time the weapon will have surpassed its intended lifetime by thirty-eight years. Designed in 1974, some of its materials are becoming obsolete. In 2017, Gen. John Hyten, then commander of U.S. Strategic Command, said, “It’s a miracle that it can even fly.”

Moreover, as Russia fields air defense systems with advanced anti-stealth capabilities and China’s anti-access/area-denial systems (A2/AD) make its airspace increasingly prohibitive, the old missile’s limitations rule it out as a viable option beyond 2030. President Obama’s Secretary of Defense, Ashton Carter described the situation eloquently: “[I]t’s not a choice between replacing these platforms or keeping them; it’s really a choice between replacing them or losing them.”

>>> The Biden Administration Must Prioritize Extended Deterrence

Forgoing LRSO development would ultimately deprive the United States of any air-launched cruise missile capability. Here are three reasons why that would be dangerous.

First, fielding the LRSO is essential to sustaining the air leg of the nuclear triad, the most flexible and visible compared to the land and sea legs. Arming bombers with only gravity bombs would not suffice.

As Gen. Timothy Ray, commander of Air Force Global Strike Command explained: “The vast majority of targets covered by the bomber leg of the triad require the employment of stand-off weapons.” To drop gravity bombs, bombers would have to fly potentially long distances between targets in enemy territory, facing air defenses along the way. Without LRSO missiles to threaten inaccessible targets, the Air Force could not perform its air-based nuclear mission.

The Air Force needs LRSO to maintain the nuclear mission of the B-52H, which will remain in our nuclear bomber fleet for decades to come. While the future B-21 bomber will carry both gravity bombs and cruise missiles, the B-52H now carries only cruise missiles, as it can no longer penetrate enemy air defenses to release gravity bombs.

Put simply, without the LRSO to enable the nuclear-capable B-52H, the Air Force will not have enough bombers to fulfill its nuclear mission. As adversary stealth detection improves over time, even the B-21 will likely need the LRSO to maintain its deterrent value.

In a Question For the Record, Sen. Deb Fischer (R–Neb.) asked General Hyten if he believes the air leg of the triad would be viable without an air-launched cruise missile capability. He responded with an unequivocal “No.”

Second, LRSO’s unique attributes contribute to the credibility of both U.S. deterrence and assurance of allies.

In contrast to gravity bombs that can only be dropped on a single target at a time, multiple LRSO missiles can be launched from bombers simultaneously, increasing the number of targets that bombers can hold at risk. The LRSO will also feature advanced stealth, boosting its survivability against advanced Russian and Chinese air defenses.

When adversaries realize that the United States can so effectively hold their targets at risk, the threat of U.S. nuclear retaliation becomes more convincing. This is especially so when it comes to defending our allies, since Washington can deploy bombers with LRSO missiles in theater to visibly show its resolve.

>>> It's Time To Get Homeland Missile Defense Right

Critics argue that these capabilities make LRSO more “useable” in a first strike, so it is destabilizing.

But Lt. Gen. James Dawkins, the Air Force’s Deputy Chief of Staff for Strategic Deterrence and Nuclear Integration, has a hard time seeing how LRSO can be used in a disarming first strike because it would fail as a surprise attack. As he explained at a recent Heritage Foundation event, “Everything we do with bombers is visible.” When “we generate them and load them up…when we fly them toward the adversary, all that’s going to be detectable.”

For this very reason, Rose Gottemoeller, former Under Secretary of State for President Obama, testified the LRSO is “valuable in maintaining strategic stability.”

Third, fielding the LRSO provides a hedge against technical risk to the rest of the nuclear triad. As Lt. Gen. Dawkins explained, “if [the Commander of U.S. Strategic Command’s] got a challenge either in the submarine leg or in the IBCM leg, he is going to look to the bomber leg to see if they can carry…the weight of…those targeting requirements.”

Bombers have the unique ability to move from off- to on-alert status and be uploaded with additional cruise missiles. Should an issue arise in efforts to modernize the rest of the triad or should a worsened geopolitical situation warrant, the LRSO can help reduce risk to America’s nuclear deterrent.

When the Obama administration identified the need to replace the current ALCM in its 2010 Nuclear Posture Review, Russia had not yet invaded Crimea, North Korea had not yet tested a long-range missile, and hope still existed that China would rise peacefully.

If the importance of modernizing the air leg of the nuclear triad was clear to President Obama in a less tense 2010, seeing the program through in today’s increasingly threatening geopolitical environment should be a no-brainer for President Biden and his team.