Once again, Obama crashes Republican primary Twitter party

In the days leading up to the Illinois primary, the press played up the possibility of an upset victory for Rick Santorum's campaign. But Mitt Romney had a good day on Tuesday, winning the Illinois contest by a comfortable margin.

The networks' projection that Mitt Romney had won led to the highest volume spike on Twitter for the evening. As in previous cases, the second highest volume spike belonged to President Obama, this time for a St. Patrick's Day reception he held at the White House, during which the president joked about his nationality:

@StevenTDennis: Obama zinger on Shamrock bowl gift: "This will have a special place of honor, alongside my birth certificate"

This is the second time we've seen Obama's leisure activities compete for attention with a Republican primary. During the Alabama and Mississippi primaries, he took in a college basketball game with U.K. Prime Minister David Cameron.

As usual, Mitt Romney dedicated the bulk of his victory speech to addressing his differences with Obama, not with his Republican rivals. Our measures of Twitter sentiment reported more favorable reception for his speech last night than on past Tuesdays.

Example positive reactions:

@Freedom's Lighthouse: Gov. Mitt Romney Delivers Strong Victory Speech after Winning the Illinois GOP Primary: "It's Time to Say 'Enoug...

@larry_kudlow #Mitt speech was #presidential. Businessman v. lawprofessor a compelling narrative for the fall. #GOP2012 #tcot

Example negative reaction:

@GreatDebateUSA.com: Mitt Romney's speech was very good. If I believed he believed any of it, I would vote for him. But I don't, and I won't. #tcot#TeamSantorum

Meanwhile, Rick Santorum's momentum coming out of last week's victories in the Deep South seems to have largely dissipated. His speech on Tuesday night was not as well-received as Romney's on Twitter. As in previous instances, automatically extracted top keywords and hashtags associated with the candidate's name highlight his campaign's emphasis on social and cultural issues. Top ones included lgbt, porn, ban, women, priest and #pornloversunite.

Ron Paul benefited from an appearance on the Jay Leno show, which led to a spike in volume later in the evening.

Example top tweets

Mitt Romney

@MarshallRamsey: Mitt Romney wins Illinois primary. Breaks out some cheesy grits and catfish to celebrate.

@mollyesque: Santorum is right: Lots of ppl still don't like Mitt Romney. But they like him better than Santorum. http://t.co/KsMcVl0g

@politicoroger: Letterman: "it was such a beautiful day today, Mitt Romney was riding on the roof of his car."

@OverlandParker: I can't wait until Mitt Romney wins the Republican Presidential nomination & removes his square jaw to reveal that he is actually John Kerry

Rick Santorum

@TweetingAllNews: #MustRead: Santorum's blunt talk is proving troublesome: In getting this far, Rick Santorum ... http://t.co/M670PmN7 via @WashingtonPost

@ApocalypseHow: Rick Santorum's wife tells women he won't take away birth control. He'll hover in their bedrooms murmuring "Don't do it lady."

@RoselynnLocks: Alan Grayson: Rick Santorum Should 'Mind His Own Business' On Porn - The Huffington Post http://t.co/3qE2qUKZ

Example retweeted quotes:

Mitt Romney

"The problem is he's still Barack Obama"

"It's time to say this word: enough. We've had enough"

"When we replace a law professor with a conservative businessman, that's going to end."

"The American economy is fueled by freedom"

Rick Santorum

"Freedom at stake in this election."

"We don't need a manager..."

"We need to pull up government by the roots"

"When I speak...I speak from the heart."