Mitt Romney posted a snarky tweet wondering why Bernie Sanders is 'so angry' — and the Vermont senator told his Republican colleague exactly why

Sen. Bernie Sanders of Vermont and Sen. Elizabeth Warren of Massachusetts were the liberal/progressive stars of Tuesday night’s Democratic presidential debate, vigorously debating the more centrist candidates on issues ranging from Medicare-for-all to immigration. The next morning, a Republican senator now representing Utah — 2012 GOP presidential nominee and former Massachusetts Gov. Mitt Romney — took a swipe at Sanders on Twitter. And Sanders fired back with a blistering response.

Romney tweeted, “Asked why @BernieSanders is so angry, the answer is simple: 28 years in Congress and never able to pass even a scintilla of his socialist agenda. All hat, no cattle.” And Sanders, in response, listed several reasons why he is angry — from “34 million Americans” lacking health insurance to millions of Americans “living paycheck to paycheck.”

“I’m angry because multi-millionaires like you and Trump have rigged our economy at the middle class’ expense,” Sanders told Romney on Twitter.

And the 77-year-old Sanders concluded his tweet with a question for the Utah senator: “Why doesn't that anger you?”