A new ABC News/Washington Post poll finds 64% of very conservative Republicans and independents now view Mitt Romney positively, up from a February low of 43%.

However, none of the Republican presidential candidates “is above water on basic popularity among all women nationally, or among men.”

Rick Klein: “Santorum is down too far in the delegate count to win only the states he’s expected to win. Santorum needs an upset. He needs it to come in a big state, and fast, for him to change the dynamics of the race sufficiently… A win in Illinois would be a different story. It may be Santorum’s last best shot to prove that he’s a contender, not merely a potential spoiler.”

A new Quinnipiac poll in Virginia shows Tim Kaine (D) leading George Allen (R) in the U.S. Senate race, 47% to 44%.

Also interesting: President Obama leads Mitt Romney by eight points in a general election match up, 50% to 42%, and tops Rick Santorum by nine points, 49% to 40%.

Missouri supporters of Mitt Romney and Ron Paul “have forged an alliance in some of Missouri’s local caucuses,” the AP reports.

“Rick Santorum easily won Missouri’s non-binding primary last month. But he was shut out from receiving delegates at some of the local caucuses that occurred over the weekend after Romney and Paul supporters combined to advance their own slate of delegates.”

Daily Beast: “In a Republican primary process that has been more convoluted than a pretentious student film, Missouri’s rules are uniquely confusing and uniquely prone to exploitation by a well-organized campaign. Paul’s operation, designed to maximize caucus-state delegates, has stepped into the void left by Santorum’s underwhelming operation.”

Illinois Republicans head to the polls today to choose their presidential nominee.

Chicago Tribune: “For a state that is home to President Barack Obama and run by Democrats, the grueling, months-long GOP battle for the nomination provides the state’s out-of-power Republicans with a real say on national politics for the first time in decades. Democratic voters, meanwhile, will decide several heated congressional contests in newly drawn districts.”

“At stake are not only Illinois’ 54 elected national convention delegates, but for Mitt Romney, the chance to gain much-needed momentum with a big-state victory. For a vastly outspent and out-organized Rick Santorum, a win in Illinois would upend Romney’s slow drive to the nomination and fuel questions about the former Massachusetts governor’s electability and ability to unify core GOP conservatives.”

Smart Politics: “Only one Illinois Republican presidential primary has been decided by less than 10 points out of 25 contests since 1912.”

Polls close at 8 pm ET.

Rick Santorum explains to Real Clear Religion why he’s losing the Catholic vote despite being Catholic himself.

Said Santorum: “I’ve heard different excuses and different explanations from different people. I think one of the reasons is that Catholics are certainly not a monolith. They don’t vote like a minority anymore; in other words, they don’t vote in a bloc. And I think that’s a good thing, actually… I think that shows that Catholics have, by and large, assimilated into the religious milieu of this country. I think that’s probably the biggest part of it. In fact, I don’t know how many Catholics actually know I am a Catholic.”

GQ reveals the Secret Service code names chosen by the top two Republican presidential candidates: Mitt Romney elected to call himself “Javelin.” And Rick Santorum chose “Petrus.”

“It’s tempting to associate a candidate’s code word with some aspect of their personality. Sometimes this is true and sometimes it is not. ‘Petrus’ is a biblical allusion — as in St. Peter, the first pope. (The Latin name is derived from the Greek word for ‘rock.’) Perhaps ‘Javelin’ is a reference to the ’60s muscle car made by American Motors Corporation, the company once run by George Romney.”

“I don’t care what the unemployment rate’s going to be. Doesn’t matter
to me. My campaign doesn’t hinge on unemployment rates and growth rates.
It’s something more foundational that’s going on.”

— Rick Santorum, quoted by National Journal.

In a surprise announcement, the Arizona Daily Star reports Ron Barber (D), the long time district director for former Rep. Gabrielle Giffords (D-AZ), said he would run for office in Arizona’s newly-drawn 2nd congressional district later this year.

Barber is already running to complete his former boss’ term in the 8th congressional district special election to be held on June 12. He is a survivor of the January 8, 2011 shooting in Tucson which also injured Giffords.

Rick Santorum’s campaign offered ABC News “a sneak peek at their in-house delegate tally, which still shows the former Pennsylvania senator trailing Romney but in a much better position to catch him.”

Here’s how the Santorum campaign sees the standings in the race for delegates: Romney 435, Santorum 311, Gingrich 158, Paul 91

Here is the ABC News delegate estimate: Romney 521, Santorum 253, Gingrich 136, Paul 50

“Their delegate equation largely rests on two key assumptions: First, that Arizona and Florida will eventually allocate their delegates proportionally rather than using their current winner-take-all scheme. Second, that delegate tallies in Iowa, Missouri and Washington State should be estimated based upon the preliminary results of ongoing county and district conventions, not on the initial ‘beauty contest’ votes.”

Roll Call lists the top ten most vulnerable House members up for re-election this year — six Republicans and four Democrats.

“He’s not overwhelming, that’s the problem through the whole damn
primary. What’s the spark? What’s the thing that gets him off and
running? No one knows.”

— Former House GOP leader Bob Michel (R-IL), quoted by Politico, on Mitt Romney.

“This is all about getting delegates. If the polls are right, we’ll pick up some delegates. That’s what it’s all about.”

— Mitt Romney, quoted by ABC News ahead of the Alabama and Mississippi primaries last week.

“I know a lot of people will talk about delegates and strategies and math and that’s all very interesting to the insiders. But I think the American people want to see someone who has the leadership, skill and experience to defeat the president, and a vision of conservatism that will get American back on track again.”

— Romney, in an interview yesterday on Fox News Sunday.