Sen. Elizabeth WarrenElizabeth Ann WarrenOvernight Finance: Lawmakers grill Equifax chief over hack | Wells Fargo CEO defends bank's progress | Trump jokes Puerto Rico threw budget 'out of whack' | Mortgage tax fight tests industry clout Michelle Obama is exactly who the Democrats need to win big in 2020 Wells Fargo chief defends bank's progress in tense Senate hearing MORE (D-Mass.) is promising to do everything in her power to keep the Senate in Democratic hands this November.

"I'm going to be out there fighting that," she said when asked about the possibility of the GOP winning Senate control. "I know which side, which party stands with American families, stands with America's middle class, who wants to give the middle class a fair shot. I'm going to be out there doing everything I can for the Democratic candidates. We've got good people in the United States Senate. We've tried to move something forward."

Warren warned against Republicans running the upper chamber.

"Take a look at the House if you want to see what happens when Republicans take over. What are they on now, is this their 50th vote to repeal ObamaCare? That's not how you run a country," she said.

The darling of liberal activists repeated that she would definitely not run for president in 2016.

She also touted her push to change student loan law to lower costs for those taking them on. The bill has become part of Democrats' election narrative that they're fighting for middle-class workers while the GOP isn't.

"Our young people are being crushed by student loan debt, $1.2 trillion in outstanding student loan debt, and it is exploding," she said. "In less than a decade, student loan debt has gone up 71 percent for the average amount that young people are borrowing. This is a crisis that now is not just affecting families that get hurt by it, it's affecting the whole economy."