First, she said he was "naive," and he said that, no, that was her problem.
Then the fight over maturity between Barack Obama and Hillary Rodham Clinton got really heated, with him calling her Thursday "Bush-Cheney lite."
Clinton shot back immediately, asking sardonically what had become of Obama's sunny "politics of hope."
By the end of the day on Thursday, the feud had wended its way from reality to cable news to YouTube, where it may very well go down as the moment when the Democratic presidential race started to get interesting.
Nobody watching politics is surprised that there is a genuine smack-down going on between the two Democratic senators, who are way ahead of the other Democratic candidates and generally considered the leading contenders for their party's nomination.
What's unusual is that it's happening this early, with six months until the first votes are cast.
The tussle, which began early this week over their positions on meeting with the leaders of hostile states, could be a turning point in the Democratic race, which has seen little direct engagement between the top two candidates until now.
Other candidates in the Democratic field jumped at the chance to distinguish themselves from both Clinton and Obama. Sen. Chris Dodd of Connecticut said their squabbling "certainly doesn't demonstrate a readiness to lead the nation."
A letter from Gates
Defense Secretary Robert Gates wrote to Sen. Hillary Rodham Clinton that a top Pentagon official did not intend to impugn her patriotism by suggesting her questions about U.S. planning in Iraq boosts enemy propaganda.
At the same time, Gates defended his aide and the author of the letter, Undersecretary for Policy Eric Edelman, calling him "a valued member" who provides "wise counsel and years of experience (that) are critically important to the many pressing policy issues facing the military."
Late Thursday, lawmakers on the Senate Armed Services Committee were told they would get the briefing Clinton had been seeking for months on the issue of troop withdrawal.
Republican John McCain dismissed questions Thursday about the decision of two advertising consultants to quit his presidential campaign, the latest in a rash of staff shake-ups.
"Oh, we'll be just fine. We've had our ups and downs. I'm happy where we are with our political and financial base. We'll do fine," the Arizona senator said at a lunch in New Hampshire.
'Party of losers'
Republican Rudy Giuliani called Democrats "the party of losers" for demanding a scheduled pullout of U.S. troops from Iraq.
"Democrats have already declared we've lost," the former New York mayor said Thursday at a Houston diner. "The Democrats want to give our enemies a timetable. Never in the history of war has a retreating army been asked to give a timetable.
Information from the Chicago Tribune and Associated Press was used in this report.