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' Jayce Henderson, Amanda VanAllen and Ben Waldron

VP PROSPECTS ABC News' Gregory Simmons: " Vice Presidential Contender Rob Portman Says It's Not About Sizzle" Vice Presidential contender and Senator Rob Portman (R-OH) has fired back at critics who say he's too boring to be Mitt Romney's running-mate. "Well I like to think I am a serious legislator and trying to get things done. That's my goal in life, to get things done. LINK

MITT ROMNEY Bloomberg's Richard Rubin: " Romney's Conflicting Tax goals Make Burden Shift Likely" Republican presidential candidate Mitt Romney's tax plan rests on a set of principles that, taken together, are difficult to reconcile. Romney wants to reduce individual income tax rates by 20 percent, keep preferential rates for capital gains and dividends, broaden the tax base to limit revenue loss, and retain the tax-burden distribution across income groups. LINK The Washington Post's Nia-Malika Henderson and Rachel Weiner: " Gay Romeny aide steps down, citing backlash over sexuality" Richard Grenell, whom Mitt Romney chose last month as his presidential campaign's national security and foreign policy spokesman, stepped down from his post Tuesday, suggesting that the conservative backlash over his sexuality prevented him from being effective in his role. LINK

The NY Daily News' Tina Moore and Jonathan Lemire: " Romney has secret meeting with Bloomberg." Mitt Romney secretly met with Mayor Bloomberg Tuesday morning in hopes of securing his endorsement, sources told the Daily News. Romney, who was in the city to mark the anniversary of Osama Bin Laden's death, had breakfast with Bloomberg at the mayor's philanthropic foundation's headquarters. Bloomberg - who did not endorse a candidate in 2008 but is expected to this year - spoke to the presumptive GOP nominee about the mayor's priorities in Washington, the sources said. LINK

The Boston Globe's Michael Levenson: " Top Romney aide quits in face of anti-gay sentiment" Mitt Romney's foreign policy spokesman, a gay man whose support for same-sex marriage infuriated social conservatives, abruptly resigned on Tuesday, saying the intense focus on his sexual orientation was making it impossible for him to do his job. Richard A. Grenell, who served as the spokesman for the US mission to the United Nations under George W. Bush, revealed he was leaving less than two weeks after he was hired. LINK

PRESIDENT OBAMA The Wall Street Journal's Janet Hook and Patrick O'Connor:  " Attack Ads Make Early Entry" President Barack Obama's re-election campaign has launched a fresh attack on Mitt Romney's personal wealth, moving to define the Republican challenger as someone who shipped jobs and his own money overseas. "It's just what you'd expect from a guy who had a Swiss bank account," says a new 30-second television ad, which says Mr. Romney moved state jobs to a call center in India when he was Massachusetts governor and American jobs to Mexico and China when he was a corporate CEO. LINK

The Hill's Ian Swanson and Jeremy Herb: " Obama risks his own 'mission accomplished' moment in Afghan war" President Obama risks having his own "mission accomplished" moment in Afghanistan nine years to the day President George W. Bush declared the end of major combat operations in Iraq. Obama's surprise trip to the war zone was timed for the one-year anniversary of Osama bin Laden's death, not Bush's May 1, 2003 landing on the USS Abraham Lincoln aircraft carrier.  LINK

Politico's Glen Thrush: " Obama's Osama Surprise."  Mitt Romney has led the parade of Republicans accusing President Barack Obama of politicizing the first anniversary of Osama bin Laden's death for political gain - delighting in what they view as Obama's "Mission Accomplished" moment. And the White House couldn't care less what the GOP thinks. LINK

RON PAUL The Washington Times' Ralph Hallow: " Paul supporters create delegate mischief" Mitt Romney may be the presumptive Republican presidential nominee, but Rep. Ron Paul of Texas is quietly racking up some organizational victories that could complicate Mr. Romney's anticipated coronation at the Republican National Convention in Tampa, Fla., this summer. LINK

OTHER The New York Times' Michael Barbaro: " In Pursuit of Mayor Bloomberg, the Reluctant Endorser" They court him over coffee and drop by when they are in town. They dangle invitations for golf and enlist friends to put in a good word. In an election year when partisanship has burned white hot and the economy has sputtered, two presidential candidates who agree on very little, Mitt Romney and Barack Obama, have reached a rare consensus: they are both determined to score the endorsement of Mayor Michael R. Bloomberg of New York, whose name is all but synonymous with Wall Street clout and nonpartisan politics. LINK

The LA Times' Melanie Mason and Matea Gold: " Outside groups flood swing states with ads targeting candidates" A hard-hitting commercial blasting President Obama's stimulus spending as a "failure" flooded television sets last week in eight swing states that will be decisive in November's presidential election. It was not the product of presumptive GOP nominee Mitt Romney, nor of the national Republican Party. Instead, it was made by Americans for Prosperity, a Virginia-based nonprofit that for months has poured millions into anti-Obama commercials. Its latest buy totaled $6.1 million in airtime. LINK

ABC NEWS VIDEOS "Mitt Romney Heckled, Called 'Racist' in NYC"  LINK

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