The super PAC affiliated with Senate Majority Leader Mitch McConnell, R-Ky., is squeezing Rep. Mo Brooks over acceptance of trip to China with his wife that was financed by groups supportive of comprehensive immigration reform.

Senate Leadership Fund backs appointed Sen. Luther Strange in the Aug. 15 special Senate election, and with two weeks to go in the race is keeping the pressure on Brooks by attempting to tie him to groups that oppose President Trump's get-tough immigration policies. The super PAC obtained the information on Brooks' trips — legal and conducted according to the rules — from required congressional filings.

According to information from SLF provided to and verified by Washington Examiner: "In March-April 2016, Brooks and his wife went on an all-expense paid, special interest-funded trip to China costing nearly $15,000...The trip was funded by several liberal groups who oppose Donald Trump's executive orders on immigration."

The groups, which funded trips sponsored by the Aspen Institute, included Carnegie Corporation of New York; Rockefeller Brothers Foundation; and Democracy Fund. The McConnell super PAC added gratuitiously that "the members of Congress who went to China with Brooks were overwhelmingly Democrats."

Brooks in a statement provided by his campaign said that Strange's supporters are being deceitful. He defended the trips as educational excursions that didn't cost the taxpayers a dime.

"This China trip was an extraordinary opportunity to learn about China first-hand. It is one thing to be briefed on or read about a geopolitical foe, it is quite another to see and experience China first-hand," Brooks said. "As a member of the House Armed Service Committee and Foreign Affairs Committee, I am very thankful I was able to participate in this trip to China and learn as much as I did about a geopolitical foe."

Strange was appointed to the Senate to succeed Jeff Sessions, who retired to become Trump's attorney general. But to earn the right to complete Sessions' full term, the senator needs to prevail in the special election. The top two finishers in the Aug. 15 special GOP Senate primary will advance to a Sept. 26 runoff if the winner doesn't garner 50 percent. The victor of that contest is considered a shoo-in in the Dec. 12 special general.

Brooks and Roy Moore, the former chief justice of the Alabama Supreme Court, pose the biggest threat to Strange. SLF has been attacking Brooks as insufficiently supportive of the president because he endorsed Sen. Ted Cruz of Texas in the 2016 GOP presidential primary and was slow to embrace Trump in the general election.

In a state where support for Trump among Republicans remains high, Brooks could be in trouble if the attack sticks. So he's pushing back. On Tuesday, Brooks unveiled a new television ad claiming that Strange is the real anti-Trump candidate in the race. "In Congress, I vote with President Trump 95 percent of the time. So who are you going to believe? Mitch McConnell, and Luther Strange?" he said in a straight to camera spot.