Scott Brown, the GOP U.S. Senate nominee in New Hampshire, believes the Senate’s “Gang of Eight” immigration bill would lead to more illegal immigration surging across the border, he said in a debate Monday night, according to Bloomberg Politics.

“No, I would not have supported that bill, because it still did not address the one thing that is very important,” Brown said when asked for his thoughts on the bill during the debate. “Whatever we do on these very important issues, I can’t provide and continue to provide incentives rewarding that illegality by EBT cards, preferential housing. I did not believe the mechanisms in there were strong enough to address that very real issue. And I also believe that it dealt with the amnesty issue a little bit too leniently.”

Incumbent Democratic Sen. Jeanne Shaheen (D-NH), whom Brown is challenging, reaffirmed her support for the “Gang of Eight” bill–which she voted for in 2013. Shaheen said:

The way to make the border secure is to do some of the things that are in that legislation. It provides for additional border security — almost double the number of border agents — 700 miles of fence, more money for interdiction and surveillance efforts, that E-Verify system. And it would have also dealt with the 11 million people who are here illegally, because they would have gotten in line behind the people who were here legally. And it would have said they have to pay fines, they have to learn English, they have to pay their taxes in order to qualify to continue to be here.

Brown’s position in opposition to the bill puts Sen. Marco Rubio (R-FL) in a tough position on Tuesday, as Brown came out swinging against Rubio’s signature legislation the night before Rubio headed up to New Hampshire to endorse and campaign for Brown.

Rubio is in New Hampshire for a foreign policy event with Brown on Tuesday.

“Rubio is in New England today to endorse Brown’s campaign and help him raise money, including a fundraiser in Atkinson, New Hampshire,” Bloomberg’s Michael Bender wrote. “This afternoon, the pair will also a hold a public event to criticize U.S. foreign policy and the 2011 withdrawal of troops in Iraq.”

Rubio has distanced himself from the Senate bill after its passage, actively working to undermine any efforts to pass it or a bill similar to it out of the House by coming out against any conference committee between the two chambers on immigration.

Rubio also has criticized President Obama’s plans for an executive amnesty, saying in a recent interview with Breitbart News that he supports efforts to undo Obama’s executive amnesty via the Deferred Action for Childhood Arrivals (DACA) program and that he no longer supports comprehensive immigration reform. 

“I continue to believe our system needs to be reformed, and I’ve learned in the last year that because of such an incredible distrust of the federal government, no matter who’s in charge, the only way you’re going to be able to deal with this issue is by first securing the border and ensuring that illegal immigration is under control,” Rubio said in the recent interview.

Rubio’s office hasn’t responded to a request for comment on Brown’s position on the Senate bill.