Gary Johnson, Republican presidential candidate, has joined Rick Santorum in condemning booing of gay soldier.

Johnson, the former governor of New Mexico, is considered the most gay friendly candidate on the stage during Thursday night's Fox News/Google Republican presidential debate.

But even Johnson kept mum during the debate when a video question submitted by Stephen Hill, a gay soldier serving in Iraq, was booed by the audience.

Referring to the recent repeal of “Don't Ask, Don't Tell,” Hill, appearing in an Army t-shirt, asked: “Do you intend to circumvent the progress that has been made for gay and lesbian soldiers in the military?”

The audience cheered when Rick Santorum called DADT repeal a “tragic social experiment” and vowed to reinstate the policy, if elected president.

During an appearance on MSNBC, Johnson told Rev. Al Sharpton that the incident was “not right.”

“If I have one regret from last evening, it's that I didn't stand up and say, you know, you're booing a U.S. serviceman who is denied being able to express his sexual preference. There's something very wrong with that,” Johnson said. (The video is embedded in the right panel of this page.)

(Related: Rick Santorum says he supports gay soldier Stephen Hill.)