In the second presidential debate on Tuesday night at Hofstra University in Long Island, New York, a reinvigorated President Obama took the fight to Mitt Romney. The president appeared far more energetic than in the first presidential debate, which was widely deemed a dominant victory for Romney. Democrats have called on Obama to challenge Romney more aggressively, and he did so early, exclaiming, "It's not true!" when the GOP candidate claimed that Obama essentially followed Romney's proposals for saving the auto industry. Here, some reactions from the Twitterverse:

Obama was so feisty that it drew some counterpunches from Romney, and the two men squared off face to face in a tense moment on the debate floor. More from Twitter, and watch the video below:

Watch the exchange: