* Can a Tea Party candidate win the presidency? In past elections, presidential nominees have sought to redefine their party in their own image, conveying a sense that they are remaking it order to appeal to the middle of the country in a general election. But as Dan Balz notes in a must-read this morning, this time around the GOP candidates have in effect declared slavish devotion to the Tea Party wing of the party, allowing it to define them, rather than the other way around.

Unlike in the 2010 elections, when Tea Party candidates were first elected to Congress, this time the public has already been given a bitter taste of what happens when the Tea Party is given a seat at the governing table. The GOP-controlled House has pushed the radioactive Paul Ryan plan to end Medicare as we know it and presided over a debt ceiling showdown that nearly resulted in economic armageddon. The Tea Party’s support has dramatically withered since 2010. But the GOP candidates have pled near-total fealty to the Tea Party, paying lip service to all its ideas and not making the slightest effort to moderate its tune in any way.

Balz quotes a Republican strategist who spells out worries in his party about what this portends for the general election:

“What Obama needs to do now is force the Republican nominee into supporting the tea party wing of the party over the next nine months,” he said. “Can you tie the nominee to the congressional Republicans? If he can do that, now you’re talking about a real problem.”

Obviously it remains to be seen whether the abysmally low public regard for the Tea Party and Congressional Republicans will taint the eventual GOP nominee. Romney, who is running as a pragmatic businessman with the tools necessary to get the economy running again, would seem to have a good shot at eluding that fate. But Romney, too, has been forced by GOP primary politics to embrace the Tea Party’s extremism.

If he is the nominee, Dems will try to force Romney into debating and defending the excesses of the Congressional GOP and the actual positions of the Tea Party, in hopes of painting him as captive to forces that prize ideological rigidity over balance, compromise, and even basic competence in governing. The aura of basic competence will likely be central to Romney’s appeal, which makes it all the more urgent that Dems find some way of undermining it.

* Obama won’t cede airwaves to 2012 GOP hopefuls: With the GOP caucusing set for today in Iowa, the President is set to deliver a speech to his Iowa supporters tonight. Obama hopes to maintain a high profile focus on the economy, inequality, and improving the lives of the middle class, even as the GOP candidates compete for the Tea Party mantle and hurl insults at one another.

* Another day, another slimy Big Lie from Romney: Romney’s latest: Obama would “poison the very spirit of America and keep us from being one nation under God.”

As I’ve been noting here, all of these attacks share a common thread, and are enabled by the fact that media figures politely continue to look the other way rather than engage just how monumental a series of Big Lies Romney continues to tell.

* No, an Iowa win won’t make Romney inevitable: If Romney wins in Iowa today, his campaign and various commentators will proclaim his nomination inevitable. Scott Conroy digs into the history and punctures the hype, explaining why even winning both Iowa and New Hampshire is no guarantee of long-term victory, because a strong second-place finisher in either state (or both) can gain momentum heading into South Carolina.

Also a possibility: A Romney victory could actually intensify the resolve of conservatives who remain skeptical of him to coalesce around an alternative.

* Romney flip flops on whether he’ll win Iowa: Romney yesterday: “We’re going to win this thing with all our passion and strength...”

Romney today: “I think I’ll be among the top group. I don’t know if that’s one, two or three, but all three of us will get a good send-off.”

* A county-by-county guide to Iowa’s results: Chris Cillizza and Aaron Blake have a nice breakdown of just what you should watch for today in order to track whether Rick Santorum is making meaningful gains on Romney.

* Rick Santorum, the GOP’s great working class hope? Don’t miss David Brooks on why Santorum, the son of a coal miner, is emerging as a cultural alternative for blue collar Republicans who are not persuaded by Willard’s efforts to bond with them by telling them over and over again how much he loves America.

* Santorum makes the conservative case against Romney: I still don’t quite understand why Romney’s rivals have failed to make this case, articulated here by Santorum, stick:

“This has been a debate about health care, that’s what the behemoth of government, the signature issue is Obamacare. We cannot put up a presidential candidate who is in basically in the same place as Obama on government-run healthcare.”

The key here is that this goes right to the heart of the very reason conservatives are settling for Romney — his alleged “electability.” After all, Romney simply can’t make the case against Obama’s signature domestic issue without exacerbating his greates weakness, i.e., the sense that he’ll say and do anything to win.

* Newt makes the conservative case against Romney: Newt Gingrich uncorks his sharpest attack yet on Romney’s fake conservatism and serial dishonesty, leaving us all to wonder why Romney’s rivals failed to make this case for so long.

* Meet Romney’s latest adviser: Steve Benen reviews the less-than-savory client list of new Romney adviser Charlie Black,and suggests that maybe, just maybe, a reporter might consider asking Romney to defend it.

* Where do the GOP candidates stand on high speed rail? Interesting read from Michael Cooper: Today’s GOP has moved so far to the right that the leading 2012 GOP candidates, some of whom once supported Federal investments in high speed rail, are now refusing to say where they stand on the issue.

This comes after Obama included rail funding in his stimulus, which obviously made it an instant nonstarter for Republicans.

* GOP candidates won’t say boo about infrastructure: Relatedly, good stuff from Politico’s Burgess Everett, who can’t seem to get a single 2012 GOP hopeful to detail whether he/she supports any plans to rebuild the nation’s infrastructure.

This, even as the GOP hopefuls continue to make creating jobs central to the campaign. One supposes Obama’s support for infrastructure spending as an engine for jobs creation has rendered it an automatic nonstarter, too.

* And from the Department of Self Promotion: This blog has managed to edge its way into the top five Post blogs in terms of page views and reader visits. Thanks again to all of you for your time commitment, comments, insights, tips, humor, and peerless heckling.

What else is happening?