Compiled by ABC News' Jayce Henderson, Amanda VanAllen, Carrie Halperin and Alicia Tejada

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

RICK SANTORUM ABC News' Jake Tapper: " Etch A Sketch Mania Takes Hold of Campaign Conversation" Rick Santorum's campaign spokeswoman Alice Stewart was dispatched to Toys R Us this morning to buy 20 Etch A Sketch toys. She handed them out at a town hall for Santorum's chief rival, Mitt Romney, in Arbutus, Md., this afternoon, and also to the press corps. LINK

NEWT GINGRICH ABC News' Chris Good: " GOP Rule Won't Block Gingrich's Chances" If Newt Gingrich fails to win five states, he might not be eligible in the first round of voting at the Republican National Convention. That doesn't mean he can't be the nominee, and it may not even complicate his chances any further than they already have been. LINK

MITT ROMNEY The Hill's Niall Stanage:  " An air of inevitability grows around Romney after decisive primary win" Mitt Romney is now within touching distance of the Republican Party's presidential nomination, after being ensnared for months in a tough battle. Romney has taken a bound forward within the past 48 hours. His resounding win in Tuesday's Illinois primary gave new impetus to his campaign's drive to present him as the inevitable nominee. The endorsement he received Wednesday from former Florida Gov. Jeb Bush further burnished the sense that influential figures in the GOP were coalescing behind him.  LINK

The New York Times' Jeff Zeleny and Jim Rutenberg: " Romney's Day to Relish Is Married by Aide's Gaffe" Mitt Romney sought to use the coveted endorsement of Jeb Bush on Wednesday to amplify his call for Republicans to rally behind his candidacy and get on with the mission of ousting President Obama. LINK

The Washington Post's Sandhya Somashekhar and Dan Eggen: " For Mitt Romney campaign, Jeb Bush and FreedomWorks announcements are good news" Mitt Romney got exactly the boost he needed Wednesday in the form of an endorsement by former Florida governor Jeb Bush, a move that came as GOP leaders and rank-and-file Republicans appeared to be coalescing around his presidential candidacy the day after a decisive primary victory in Illinois. LINK

The Washington Times' Seth McLaughlin: " Evangelical states sketchy for Romney" Mitt Romney's lopsided victory in Illinois this week showed again that he's hard to beat in states with more moderate, less evangelical-minded voters - a good sign for the former Massachusetts governor when that describes most of the big prizes left on the Republican primary schedule. LINK

The Wall Street Journal's Janet Hook: " Leaders Urge GOP to Unify, Back Romney" Republican officials and strategists, increasingly weary of the divisive presidential-primary fight, stepped forward Wednesday to call for the party to unify behind Mitt Romney and for his rivals to accept his nomination as inevitable. Former Florida Gov. Jeb Bush came off the sidelines and endorsed Mr. Romney for president Wednesday, a day after Mr. Romney's sweeping win in the Illinois primary. LINK

Bloomberg's Lisa Lerer: " Romney Wins Where it Counts: Collecting Money, Delegates" With yesterday's 12-percentage-point victory in Illinois over chief rival Rick Santorum, which netted about 42 of the 54 delegates at stake, Romney is almost halfway to obtaining the 1,144 he needs to capture the Republican presidential nomination. To finish the job, he must get 46 percent of the remaining delegates.  LINK

Boston Globe's Matt Viser: " Words boost, bedevil Romney" Mitt Romney sought to capitalize Wednesday on his sweeping victory in Illinois, hailing the surprise endorsement from one of his party's beacons, Jeb Bush, while trying to corral support from other prominent Republicans. Yet comments from his own top adviser inadvertently evoked a nagging challenge for Romney to lock up the GOP nomination for president. LINK

SUPERPACS The Los Angeles Times' Melanie Mason and Matea Gold: " Billionaires keep pouring millions into 'super PACs'" Billionaire political patrons filled the coffers of the presidential "super PACs" last month, spotlighting once again the enormous influence a tiny cadre of wealthy donors is having on the 2012 race. The biggest donations came from casino magnate Sheldon Adelson and his family, who pumped an additional $5.5 million into the pro-Newt Gingrich super PAC Winning Our Future in February - 95% of the money the group raised, according to documents filed Tuesday with the Federal Election Commission. LINK

USA Today's Fredreka Schouten, Christopher Schnaars and Gregory Korte: "Big-bucks donations to super PACs keep the GOP race going" More than two-thirds of the money to super PACs aligned with presidential candidates came from megadonors who each contributed $500,000 or more, demonstrating how a handful of wealthy interests have helped turn the GOP presidential primary into the longest-running nomination fight in a generation. No group relied more heavily on a few super donors than the political committee backing former House speaker Newt Gingrich: 96% of contributions to the pro-Gingrich Winning Our Future came from this elite group, a USA TODAY analysis shows. LINK

ABC NEWS VIDEOS " Romney Responds to Etch-A-Sketch Comparison" LINK " Gingrich Slams De Niro for First Lady Joke" LINK

BOOKMARKS The Note: LINK The Must-Reads Online: LINK Top Line Webcast (12noon EST M-F): LINK ABC News Politics: LINK The Political Punch (Jake Tapper): 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