Sanders addressed the question head on Monday night in a Democratic town hall sponsored by CNN.
"I am probably the most progressive member in the United States Senate, but I have–over the years not only in the Senate, but in the House–worked with Republicans when there was common ground," Sanders said.
"In a number of years, I got more amendments passed in the House, working with Republicans than anyone else," Sanders said.
Rolling Stone author Matt Taibbi nicknamed Sanders the "amendment King" in a 2005 story on the "horror show that is Congress."
But as Sanders noted during the CNN event, his biggest lift in Congress came in 2014 amid a Veterans Affairs scandal that exposed that dozens of veterans died awaiting care at a Phoenix VA hospital. Sanders–the chairman of the Senate's Veterans Affairs Committee at the time– worked closely with Sen. John McCain (R-AZ) and Rep. Jeff Miller (R-FL) to fix the problem. And in a matter of months, there was new legislation that was signed by the president.
Sanders called it "the most comprehensive veteran's health care legislation in the modern history of the United States of America."
But Sanders added that his working with Congress would also have to be interspersed with systematic change.
"In my view, you have a Congress today that is much more worried about protecting the interests of the wealthy and the powerful and making sure they get campaign contributions from the wealthy and the powerful."