And perhaps most notably, the feel was simply different. The president faced a press corps that at times seemed exasperated and was quick to challenge him, and Mr. Obama seemed more frustrated with his questioners than he has been in the past.
The primary point of contention was Iran. The president opened the press conference by ratcheting up his rhetoric, saying he is "appalled and outraged" by the violence and threats against protesters. He had been criticized in recent days by John McCain and others for not offering stronger criticism of the Iranian regime.
That prompted this question from Fox News' Major Garrett: "What took you so long?"
The president responded by saying, in part, "we've been entirely consistent, Major, in terms of how we've approached this."
That's a stretch – the president had previously been nowhere near as strong in his criticism as he was today. He was later short with Garrett, repeating exact words in response to a follow up on potential diplomatic relations with Iran.
Before you say, "hang on, this is conservative-leaning Fox you're talking about, it doesn't mean all that much," consider the fact that an even more contentious back-and-forths took place with other correspondents.
Here's an exchange between Mr. Obama and NBC's Chuck Todd:
Todd: Mr. President, I want to follow up on Iran. You have avoided, twice, spelling out consequences. You've hinted that there would be from the international community, if they continue to violate -- and you said "violate these norms." You seemed to hint that there -- there are human rights violations taking place.The next questioner was ABC's Jake Tapper, who opened, with, "Before I ask my question, I wonder if you could actually answer David's [on health care]." Mr. Obama didn't seem to like that.
MR. OBAMA: I'm not hinting. I think that when a young woman gets shot on the street when she gets out of her car, that's a problem.
Todd: Then why won't you spell out the consequences that the Iranian people...
MR. OBAMA: Because I think that we don't know yet how this thing is going to play out. I know everybody here is on a 24-hour news cycle. I'm not. OK?
"You think you're going to -- are you the ombudsman for the White House press corps?," he asked. "What's your question -- is that your question?"
The president soon attempted an uneasy joke after Tapper's question referenced Mr. Obama's "Spock-like language about the logic of the health care plan" – the president quipped "is that a crack on my ears?" – but it fell flat.
Mr. Obama would later knock a reporter's attempt to tie his smoking habit to yesterday's tobacco legislation because, he argued, the bill is focused on children.
"I think it's fair, Margaret, to just say that you just think it's neat to ask me about my smoking as opposed to it being relevant to my new law," he said.
With Bloomberg's Hans Nichols, the president got into a mini-argument about whether he would prognosticate about the ceiling for the unemployment rate; when Helen Thomas interjected as he was answering a question toward the end, he told Thomas to "hold on a second" but did not go back to her.
At one point, CBS News' Chip Reid asked if Mr. Obama was "influenced at all by John McCain and Lindsey Graham accusing you of being timid and weak." Responded Mr. Obama (albeit with a smile): "What do you think?"
All this said, the overall tone of the press conference was certainly civil. It just wasn't quite as civil as it has been in the past. Is this evidence that the press corps is turning against the president? That might be a stretch. But it does seem to reflect the fact that reporters have clear lines of inquiry on issues like Iran, health care and the economy -- and that Mr. Obama does not seem to be able to dismiss them quite as easily as he might like.
More Coverage Of Obama's Press Conference:
Obama: "Appalled And Outraged" At Iran Violence
Obama Lauds Public Health Care Option, But Stops Short Of Ultimatum
Obama Acknowledges Occasional Smoking Habit
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Highlights: Obama's Press Conference
Analysis: A More Contentious Obama Press Conference
Washington Unplugged: Obama Ratchets Up Iran Rhetoric