Republican politicians responded almost reflexively to the North Korean nuclear test on Tuesday by demanding more spending on missile defense programs that have historically proved ineffective at preventing an enemy strike — but are built by companies that have lavished policymakers with campaign cash and political support.

Sen. Tom Cotton, R-Ark., released a statement calling for the country to “reinvest in missile defense and our military presence in the Pacific.” Rep. Mike Rogers, R-Ala., called for Obama to “dramatically enhance trilateral missile defense” and declared that Obama should deploy a Lockheed Martin missile defense system in South Korea. Raytheon and Lockheed Martin are among his top donors. Rep. Mac Thornberry, R-Texas, issued a statement specifically calling for spending on that same program; Lockheed Martin is by far his biggest donor over the course of his congressional career.

Since the early 1990s, politicians of both parties have cited the threat of North Korea to demand funding for an array of missile defense programs that quickly became monumental examples of government waste. Meanwhile, the contractors involved in these projects, including Lockheed Martin, Boeing, and Raytheon, among others, have manipulated the politics around these programs by funding politicians, pundits, think tanks, and lobbyists behind the never-ending spiral of taxpayer spending.

More than $50 billion has been spent on ineffective missile defense programs so far — the result of efforts that often began by citing the threat of states such as North Korea. Consider:

The government has spent roughly $40 billion on the Ground-based Midcourse Defense system, managed by Raytheon and Boeing, a program designed to counter a missile from North Korea. An investigation by the Los Angeles Times found that when the program has been tested, even with carefully scripted conditions in which the system operators knew the exact location, trajectory, speed, and dimensions of test missiles, the GMD intercept systems failed consistently. The project won funding from politicians like Sen. Jeff Sessions, R-Ala., who cited the “prospect of a long-range ballistic missile launch from North Korea.”

Another Los Angeles Times investigation found a series of failed missile defense systems, including a plan to use infrared chemical lasers mounted on planes to destroy enemy missiles. The lasers were deemed too weak at the distance required to operate them safely, killing the project, but not before Boeing, Northrop Grumman, and Lockheed Martin collected around $5.3 billion for the program.

The Kinetic Energy Interceptor, a project by Northrop Grumman and Raytheon, is another failed missile interception system that was canceled after Navy officials found multiple problems, including its size and limited range. The program cost approximately $1.7 billion. Sen. Richard Shelby, R-Ala., said funding for the KEI was necessary “particularly in light of the missile threats from North Korea.”

The Multi-Object Kill Vehicle program by Raytheon and Lockheed Martin cost $700 million to develop, but was canceled in 2009 after military officials found that the anti-missile program faced insurmountable technical challenges. Last year, however, the program was relaunched after congressional leaders inserted language into the 2016 Pentagon budget that called on military planners to redevelop the effort.

The Sea-Based X-Band Radar, a floating radar designed to detect enemy missile launches, failed after tests found that the radar has a limited field of vision and was highly vulnerable to corrosion at sea. The project, managed by Boeing Raytheon, cost $2.2 billion. The “huge golf-ball-like radar craft” sat idle for months in Pearl Harbor as military planners figured out what to do with the enormous flop. The late Sen. Daniel Inouye, D-Hawaii, was a major proponent of the radar, citing the threat of North Korea.

The Precision Tracking Space System, which called for a network of up to a dozen satellites used to track missile launches, was quietly killed after experts found that the system was fundamentally flawed. The government spent more than $230 million on the project, which went to contractors including Northrop Grumman.

And an 18-year, $2.7 billion Raytheon program called JLENS, or “Joint Land Attack Cruise Missile Defense Elevated Netted Sensor System,” now appears doomed after one of two blimps intended to spot and shoot down cruise missiles broke free and made a destructive trip through Pennsylvania in October during testing.

The biggest boosters of these missile defense boondoggles are funded by the contractors that have profited from them. The Heritage Foundation and the American Enterprise Institute, two think tanks that routinely issue reports and dispatch their experts to television programs to call for such spending to counter the North Korean threat, are both funded by major defense contractors that have managed missile defense projects.

There are many ways contractors wield influence over the defense policy process. For instance, companies like Northrop Grumman and Lockheed Martin spend tens of millions of dollars on lobbying, and often lure congressional staffers and officials at the Pentagon to work for them with extremely generous pay packages. To ensure loyal members of their team continually move in and out of the policymaking world, Northrop Grumman even has a special bonus for executives who leave the company to take high-level government jobs.

Top photo: North Korean soldiers march during a military parade to mark 100 years since the birth of North Korea’s founder, Kim Il-Sung, in Pyongyang on April 15, 2012.