Sen. Rand Paul, R-Ky. speaks during a stop with local Republicans, Tuesday, Aug. 5, 2014, in Hiawatha, Iowa. (AP Photo/Charlie Neibergall)

WASHINGTON -- Sen. Rand Paul (R-Ky.) on Wednesday called on President Barack Obama to seek congressional authorization for any prolonged military operations in Iraq, especially if it involves "troops on the ground."

"The American ppl deserve a full debate & for their leaders to act within the Constitution re: deeper military involvement in #Iraq," he said in a tweet.

The libertarian-leaning Republican, a potential 2016 presidential contender, has long been skeptical of entangling the U.S. in foreign affairs. His previous positions against American intervention in Syria, Libya and Iraq have prompted critics, including many from the establishment wing of the GOP, to argue that America cannot afford to isolate itself at a time of global turmoil.

Reaction on Capitol Hill was swift after President Barack Obama announced his decision to launch limited airstrikes against Islamic State militants in Iraq last week. But Paul notably reserved judgment for four days before gingerly addressing the subject at an event in Kentucky on Monday.

"I have mixed feelings about it. I'm not saying I'm completely opposed to helping with arms or maybe even bombing, but I am concerned that ISIS is big and powerful because we protected them in Syria for a year," he said at the Campbellsville Chamber of Commerce. "Do you know who also hates ISIS and who is bombing them? Assad, the Syrian government. So a year ago, the same people who want to bomb ISIS wanted to bomb Syria last year. Syria and ISIS are on opposite sides of the war. We're now bombing both sides of one war that has spread into another country."

The Pentagon on Wednesday sent 130 more "military advisers" to northern Iraq to aid Kurdish forces in their fight against militants who threaten an American consulate in Erbil.