Senator Rand Paul (R-KY) railed against his colleagues in the Senate Foreign Relations Committee on Tuesday for voting to arm elements of the Syrian opposition, saying they chose to fund “the allies of al-Qaeda.”

“This is an important moment,” Paul said following the vote. “You will be funding, today, the allies of al Qaeda. It’s an irony you cannot overcome.”

The Senate bill, co-sponsored by senators Robert Menendez (D-NJ) and Bob Corker (R-TN), authorizes the United States to directly arm Syrian rebels that have gone through a so-called vetting process.

“Paul offered an amendment that would strike the bill’s weapons provision,” reports John Hudson at Foreign Policy, “but it was rejected along with another Paul amendment ruling out the authorization of the use of military force in Syria.”

For more than a year, the CIA has been facilitating the delivery of arms from countries like Saudi Arabia and Qatar to Syrian rebel groups, although the Obama administration has stopped short of a decision to directly arm the rebels. This bill is aimed at pushing the president in that direction.

“The evidence is mounting that Syria has become a magnet for Sunni extremists, including those operating under the banner of Al Qaeda,” The New York Times almost a year ago. And in the past year, that reality has metastasized, with Jabhat al-Nusra – categorized by the State Department as an official terrorist organization with ties to al-Qaeda – developing into the rebels’ main fighting force.

Rand Paul was evidently skeptical of claims that rebels receiving arms will be vetted to ensure extremists don’t receive them. And with good reason: the process is made up of untrustworthy, third-party sources and intelligence officials told the Washington Post and the Los Angeles Times as far back as a year ago that the truth is that the U.S. doesn’t know who is getting the money and weapons.

Eager to get more involved in the Syrian civil war, the Senate committee pledged to send arms to groups with known ties to jihadist extremists. The blowback from America’s last such venture, with the Afghan mujahideen in the 1980s, was the infamous terrorist attacks on New York and Washington on September 11, 2001.

How it will blow back at America in the future is not yet known.