Before summer recess, the Senate roundly rejected the White House’s attempt to kill off one of this country’s most storied missile technologies.

The Senate Defense Committee instead approved a 2015 draft appropriations bill adding nearly $80 million to the line item for production of Tomahawk cruise missiles. These senators are following in the footsteps of their chamber counterparts — the House Armed Services Committee passed a defense bill boosting Tomahawk production earlier this year.

Congress’s enthusiasm for this missile system is in direct defiance of the White House, which tried to cut next year’s funding for the Tomahawk and hoped to completely strip its financing by 2016.

Legislators were smart to preserve the system. The Tomahawk missile is an essential technology for protecting the American people and further international order. But this fight is not over. Congressional appropriations expire after one year. Lawmakers must stay vigilant and continue to fight for the Tomahawk.

Although drones have been getting all the headlines these days, Tomahawk cruise missiles remain a mainstay of our fighting forces. They have been fired more than 2,000 times in combat, including the 2011 NATO-led effort against Libyan leader Muammar Gaddafi.

Despite its evident utility, the White House wanted to shelve this system and then gamble billions on a futuristic — and thoroughly unproven — replacement system called the Long Range Anti-Ship Missile (LRASM).

Such speculative investments have an unfortunate history of not panning out. The Pentagon spent $11 billion on the Crusader, which was supposed to be a next-generation howitzer. Instead, it ended up in the scrap heap after it turned out to be immobile and imprecise.

Then there was the Comanche helicopter, which included stealth technology among other new design features. After plowing $7 billion into the project, the Army eventually killed it and spent the savings renovating its existing fleet of helicopters instead.

The precursor project to LRASM specifically is not exactly confidence-inspiring. It grew out of the Joint Air-to-Surface Standoff Missile, which began development in 1995. After numerous failed tests and costly refinements to the design, the missile finally made it into service in 2009.

Given this troubling record and the realities of today’s budgetary limits, it’s more than a little disturbing that the White House would want to go down the same road again. Indeed, since the Tomahawk system is already up and running, the federal government can simply buy the missiles it needs, instead of investing untold amounts developing an entirely new missile program.

Of course, we must continue to invest in the weapons technology of the future. Just as world dangers don’t adjust to our current budget woes, global war-fighting technology doesn’t sit still.

The plan to replace the Tomahawk with LRASM also runs the risk of creating a gap in our missile capabilities. The old, proven system would have been shuttered. The new replacement would almost certainly have suffered lengthy — and costly — delays. And in the interim America’s military personnel would be without a core defense technology.

Without a fully operational missile program, American interests would be far more vulnerable to attack. When considering a strike, our enemies know to expect a swift U.S. missile response. As a submarine-based system, the Tomahawk is an especially strong deterrent, as it can deliver surprise attacks by remaining completely hidden until a missile is launched.

What’s more, missiles have none of the drawbacks of alternatives like drones and manned aircraft. Using manned aircraft to take out well-protected targets necessarily risks the lives of the air crew. The Tomahawk not only keeps American military personnel out of harm’s way; it delivers the same level of accuracy as manned aircraft at a lower cost.

And while drones such as the Predator or Reaper might be effective against terrorists, they are no match for the air defense systems of nations like Iran. As Gen. Mike Hostage, chief of the air service’s Air Combat Command, said last year, “Today I couldn’t put [a Predator or Reaper] into the Strait of Hormuz without having to put airplanes there to protect it.”

By contrast, the Tomahawk was designed for missions against heavily-defended targets, including integrated air defense systems.

Americans must remain vigilant against future efforts to scrap what’s tried and true. As an older program, Tomahawk often finds itself on the chopping block during annual budget deliberations.

When times are tight, we need to focus on investments that offer high payoffs at relatively low cost and risk. In the case of cruise missiles, replenishing and upgrading our supply of Tomahawks is the best way to meet our requirements in a world seemingly poised for a new era of instability from the Black Sea to the Persian Gulf.

Andrew Garfield is a senior fellow at the Foreign Policy Research Institute, where he works on national security.