Dick Cheney, the intellectual godfather of GOP foreign policy, warned in a speech Tuesday that the pending deal with Iran “will give Iran the means to launch a nuclear attack on the U.S. homeland.”

That should sound familiar. It’s the same argument used by Cheney and others to justify the disastrous invasion of Iraq, which as you’ll recall was necessary to prevent “mushroom clouds over American cities.” But it goes much deeper than that.

If you look through history, Cheney has opposed almost every arms control treaty the United States has negotiated for more than 3o years, including a 1987 pact negotiated and signed by President Ronald Reagan with the Soviet Union. And time and again Cheney has been proved wrong.

For example, he bitterly opposed a 1991 treaty that required the United States to give up chemical weapons, claiming that it too would leave us vulnerable to attack. He also argued against the Nunn-Lugar Act, co-authored by the legendary Sam Nunn, dismissing it as “foolish.” In reality, Nunn-Lugar proved an immense success in ensuring that thousands of nuclear weapons in the various Soviet republics after the USSR’s collapse were deactivated and destroyed, with none falling into the wrong hands. The world would be a much more dangerous place had Cheney gotten his way.

It’s also important to note the stark contrast between Cheney and much of the “old-school” Republican foreign policy leadership. In comments over the weekend, for example, former Secretary of State Colin Powell — who also served as Reagan’s national security adviser — called U.S. accomplishments in that deal “remarkable” and “very, very important.”

Gen. Brent Scowcroft, who served as national security adviser to President Gerald Ford and President George H.W. Bush, argues that the upcoming congressional votes will determine “whether the United States has the will and sense of responsibility to help stabilize the Middle East, or whether it will contribute to further turmoil, including the possible spread of nuclear weapons.”

“To turn our back on this accomplishment would be an abdication of the United States’ unique role and responsibility, incurring justified dismay among our allies and friends,” Scowcroft says. “We would lose all leverage over Iran’s nuclear activities. The international sanctions regime would dissolve. And no member of Congress should be under the illusion that another U.S. invasion of the Middle East would be helpful.”

Former Sen. Richard Lugar, longtime chair of the Senate Foreign Relations Committee, also embraces the deal, warning that “Rejection of the agreement would severely undermine the U.S. role as a leader and reliable partner around the globe. If Washington walks away from this hard-fought multilateral agreement, its dependability would likely be doubted for decades.”

Ordinarily, you might look at those comments by longtime Republicans with real foreign policy expertise, contrast them with Cheney, and conclude that there’s a difference of opinion within the GOP. You’d be wrong. Within the narrow confines of the GOP, Cheney’s opinion is the only opinion tolerated. No Republican will vote in favor of the deal because doing so would mean they are no longer Republican.

That’s a problem.