The Note's Must-Reads are a round-up of today's political headlines and stories from ABC News and the top U.S. newspapers. Posted Monday through Friday right here at www.abcnews.com

Compiled by ABC News' Carrie Halperin , Jayce Henderson, Amanda VanAllen and Will Cantine

S&P LAWSUIT The Los Angeles Times' Alejandro Lazo and Andrew Tangel: " Justice Department sues S&P over mortgage bond ratings " The federal government is embarking on one of its most ambitious efforts to assign blame for the financial crisis, going after Wall Street's biggest credit rating firm for its role in pumping up the housing bubble. The Justice Department filed a lawsuit late Monday in Los Angeles federal court against Standard & Poor's Corp. LINK

GUN CONTROL ABC News' Mary Bruce and Devin Dwyer: " Obama Cites 'Murder-apolis' Turnaround As He Takes Gun-Control Push On The Road" Presdient Obama took his plan to overhaul the nation's gun laws on the road to Minneapolis, Minn., Monday, making a public push for lawmakers to act in a state where efforts to reduce violence are showing "that progress is possible." LINK

USA Today's Paul singer and Gregory Korte: " USA TODAY Survey: More Republicans In Congress Own Guns" Republicans in Congress are much better armed than their Democratic counterparts - a fact that helps explain the deep partisan divide as Congress gears up for its first major votes on gun control in a decade. One hundred nineteen Republicans and 46 Democrats declared themselves as gun owners in a USA TODAY survey of lawmakers. LINK

The Washington Post's Philip Rucker: " Obama takes gun control push to law enforcement, American people" President Obama, taking his first trip outside Washington to rally support for new gun measures, stood alongside dozens of uniformed police officers here Monday as he delivered a forceful defense of mandatory background checks for all gun buyers. Obama also touted his proposed bans on assault weapons and high-capacity ammunition magazines during a speech at the Minneapolis Police Department's Special Operations Center, signaling his intent to keep pushing for several major policy changes in Congress. LINK

IMMIGRATION

The Wall Street Journal's Melanie Trottman, Miriam Jordan and Kris Maher: " Unions Seize On Immigration Debate" Labor Unions are throwing their political muscle behind lawmakers' efforts to overhaul immigration regulations, with the hope that organizing immigrant workers can swell union's shrinking ranks. On Tuesday, AFL-CIO President Richard Trumka and other labor leaders are set to meet with President Barack Obama on immigration, along with chief executives from companies including Coca-Cola Co. and Goldman Sachs Group Inc. LINK

The Washington Times' Stephen Dinan: " Congressional staff jobs provide 'dreamers' a leg up to citizenship" Two immigrants have gone from illegal to congressional in a matter of months. Erika Andiola and Jose M. Quintero gained tentative legal status under President Obama's non-deportation policy for young adults that took effect in August, and both have been hired to work in district offices for members of Congress. Coming in the middle of the immigration debate, the hirings are freighted with symbolism about the bargain Mr. Obama and many in Congress want to offer illegal immigrants: come forward, register and be given legal status. LINK VOTING

The New York Times' Jeremy W. Peters: " Waiting Times at Ballot Boxes Draw Scrutiny" With studies suggesting that long lines at the polls cost Democrats hundreds of thousands of votes in November, party leaders are beginning a push to make voting and voter registration easier, setting up a likely new conflict with Republicans over a deeply polarizing issue. White House officials have told Congressional leaders that the president plans to press for action on Capitol Hill, and Democrats say they expect him to highlight the issue in his State of the Union address next week. LINK

CHUCK HAGEL

Politico's Manu Raju and David Rogers: " McCain: Don't filibuster Hagel" Sen. John McCain appears to have cleared the way Monday for Chuck Hagel to be the next secretary of defense. The Arizona Republican, who has been a prominent voice in the debate over Hagel, said Monday he would oppose any attempt to filibuster the nomination, likely dooming any attempt by Senate conservatives to sustain a protracted procedural fight to delay Hagel's confirmation. LINK

GOP / TEA PARTY The Boston Globe's Frank Phillips: " GOP is finding few takers for Mass. Senate Race" Three more high-profile Republicans, in rapid succession, withdrew their names from the special US Senate election Monday, leaving the GOP with the prospect of fielding a relative unknown in what the party had hoped would be a pitched battle for John F. Kerry's former seat. Just three years after Republicans triumphed in Scott Brown's unlikely victory to replace the late Senator Edward M. Kennedy, the only GOP candidate actively pursuing a campaign is a 47-year old Cohasset businessman whose only electoral experience is a failed bid for town selectman. LINK

Bloomberg's Julie Bykowicz: " Rove's Move Into Republican Primaries Enrages Tea Party" Leaders of the anti-tax Tea Party are fuming about plans by some Republican strategists, including Karl Rove, to tap the party's wealthy donors and raise money to help "electable" candidates win primary races. Jonathan Collegio, a spokesman for Conservative Victory Project, said in an e-mail yesterday that Republicans lost some Senate races last year and in 2010 because of "undisciplined candidates running bad campaigns." The new group "seeks to help elect the most conservative candidates in Republican primaries who can win in general elections." LINK

BOOKMARKS The Note: LINK The Must-Reads Online: LINK Top Line Webcast (12noon EST M-F): LINK ABC News Politics: LINK George's Bottom Line (George Stephanopoulos): LINK Follow ABC News on Twitter: LINK ABC News Mobile: LINK ABC News app on your iPhone/iPod Touch/iPad: LINK