* John Nichols makes a striking point about Dems’ collection of a million signatures to recall Scott Walker: It “represents 46 percent of the turnout in the 2010 Wisconsin gubernatorial election.”

* Alex Seitz-Wald makes another key observation: “The number of signatures comes close to the 1,128,941 votes Walker received.”

* Paul Krugman asks a good question about Romney’s 15 percent interest on investment income:

how much of that is true investment income, and how much is carried interest, which is actually earned income that for reasons unclear manages to get taxed like investment income (making nonsense of the claim that investment income should face low taxes because it has already been taxed once)?

* Sarah Kliff adds much more:

It’s likely he also benefited from related tax privileges during his time at Bain. While the lower rate on capital gains and dividend income is supposed to benefit investors, private-equity executives and hedge-fund managers who get paid by taking a share of their firm’s profits rather than a normal salary are also able to classify their income as a capital gain rather than a wage, and so they, too, pay a 15 percent tax rate — even when that money is, effectively, their salary. Ultimately, the private-equity tax loophole could become far more controversial than whether private-equity deals destroy or create jobs.

* Ari Berman on the odd and disconcerting sight of GOP presidential candidates making racially questionable assertions on, of all days, Martin Luther King day.

* Obama reelect reality check of the day: The new Post poll finds Romney leading Obama 50-38 among independents (though Obama bests Romney among “moderates” by 54-40.

* Peyton Craighill parses the new Post data showing that the criticism of Romney’s Bain years may have limited resonance in the GOP primary but could matter in the general.

* The next big labor brawl: The Communications Workers of America ramps up as the battle again heats up over the House GOP drive to keep a union-busting provision in the FAA reauthorization bill.

* Conservative anti-Romney primal scream of the day: John Hawkins’ rant on why Romney will be an “atrocious” general election candidate and why it’s insane for conservatives to tar any and all questions about Bain as anti-capitalist.

* Rick Santorum drops hard-hitting mailers in South Carolina skewering Romney’s ideological opportunism, the latest in Santorum’s efforts to emerge as the only credible anti-Romney conservative.

* Fun fact of the day, with ominous implications for 2012: Super PACs are outspending the actual GOP presidential campaigns in South Carolina by two to one.

* And the GOP’s rightward drift has turned even climate change, a.k.a. the fate of the earth, into a culture war issue.

What else?