Presidential hopeful Bernie SandersBernie SandersSanders on Cheney drama: GOP is an 'anti-democratic cult' Briahna Joy Gray: Biden campaign promises will struggle if Republicans win back Congress Biden backs COVID-19 vaccine patent waivers MORE, the Independent senator and self-described democratic socialist, says that now in his heart he considers himself a Democrat. 
"Of course I am a Democrat and running for the Democratic nomination," Sanders told a New Hampshire town hall on Wednesday night. 
CNN host Anderson Cooper, the moderator of the town hall, had asked Sanders about a tweet from Sen. Barbara BoxerBarbara Levy BoxerBottom line Trump administration halting imports of cotton, tomatoes from Uighur region of China Biden inaugural committee to refund former senator's donation due to foreign agent status MORE (D-Calif.), who attacked Sanders as an occasional Democrat.
Responding to Sanders's comment that Democratic front-runner Hillary ClintonHillary Diane Rodham ClintonMcConnell: Taliban could take over Afghanistan by 'the end of the year' Hillary Clinton: There must be a 'global reckoning' with disinformation Pelosi's archbishop calls for Communion to be withheld from public figures supporting abortion rights MORE was a progressive on "some days," Boxer, a Clinton ally, tweeted, "Hillary is a progressive EVERY day. Bernie is a Democrat 'some days.'" 
After quoting Boxer, Cooper asked Sanders, "In your heart, are you a Democrat?"
"Sure," Sanders replied, citing his long tenure in the House and Senate Democratic caucuses, albeit as an Independent.
He went on to say that Clinton cannot claim to be both a moderate and a progressive.
"You can't go and say you're a moderate on one day and be a progressive on the other day.
"Some of my best friends are moderates. I love moderates. But you can't be a moderate and a progressive. They are different."
Sanders tried to play down expectations that he would secure a strong victory in New Hampshire, given he is currently ahead by almost 20 percentage points in the latest RealClearPolitics average.
"Of course we’re an underdog," Sanders said. "We are taking on the most powerful political organization in the country and that’s the Clinton organization."