REUTERS/Kevin Lamarque REUTERS/Kevin Lamarque Two of the leading candidates for president are trolling each other on Twitter.

In what could be a preview of a potential general-election race, former Secretary of State Hillary Clinton and former Gov. Jeb Bush of Florida repeatedly exchanged shots on Monday, posting images to mock each other with sarcastic tweets.

Their back-and-forth began when Clinton, the Democratic front-runner, touted her new college-affordability plan:

Bush decided to jump into the conversation by repurposing Clinton's image to argue that President Barack Obama, under whom Clinton once served, had done little to address the college-affordability issue:

Clinton has gone out of her way recently to attack Bush. And, sure enough, her campaign responded directly to his Twitter broadside. The Clinton campaign took Bush's image, scribbled new text on top of it, and declared that his gubernatorial record had an "F" grade on college affordability in Florida:

Bush, perhaps hoping to win favor among GOP voters, has similarly embraced an aggressive strategy with Clinton. His campaign responded to Clinton late Monday evening by "fixing" her signature campaign logo to point upward with "TAXES" written repeatedly in the background: