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, Amanda VanAllen and Jordan Mazza

US-MEXICO RELATIONS ABC News' Mary Bruce: "In Mexico, President Obama Says Immigration Reform Is Critical to Trade" President Obama arrived in Mexico City today, where the economy and trade were intended to top the agenda of his three-day trip to Mexico and Costa Rica. With Congress poised to overhaul the nation's immigration laws, however, border security and immigration reform are overshadowing much of the public discussion. LINK

The Wall Street Journal's Colleen McCain Nelson and Peter Nicholas: " Mexico, U.S. Leaders Try To Deepen Economic Ties" President Barack Obama offered his support Thursday for Mexico's shifting security strategy as he called for a greater focus on economic ties in a relationship between the two countries that often has been dominated by issues of drugs and illegal immigration. Mr. Obama arrived for a two-day visit amid signs that Mexico is moving to reduce the violent tempo of its yearslong war against drug traffickers. At the same time, President Enrique Peña Nieto is revamping his law enforcement bureaucracy, a move that will affect coordination with U.S. agencies. LINK

MORNING AFTER PILL USA Today's Aamer Madhani: "Obama supports new FDA rule on morning-after pill" President Obama on Thursday said he supports a decision by the Food and Drug Administration to allow girls aged 15 and older to buy the morning-after pill without a prescription. "I'm very comfortable with the decision they've made right now, based on scientific evidence," Obama said during a news conference in Mexico City. LINK

COMMERCE DEPARTMENT Politico's Jennifer Epstein: " No progress on Obama's big Commerce plans" Last January, President Barack Obama laid out a sweeping plan in an East Room ceremony to eliminate the Commerce Department and replace it with a more agile agency to lead on commerce and trade issues. A week before the election last November, he went further, calling for a "Secretary of Business" to lead a "one-stop shop" that would help companies get loans and deal with trade issues. LINK

The New York Times' Jackie Calmes: " Obama Picks Nominees for Commerce Dept. and Trade Representative" President Obama rounded out his second-term cabinet choices on Thursday, nominating Penny Pritzker, his longtime financial backer and an heir to the Hyatt Hotel fortune, to be commerce secretary, and Michael Froman, a law school friend and White House adviser on international economics, as trade representative. Mr. Obama introduced his two friends in a Rose Garden announcement just before departing for a three-day trip to Mexico and Costa Rica, along with Mr. Froman. LINK

VICE PRESIDENT BIDEN The Washington Post's Philip Rucker: " Biden ponders a 2016 bid, but a promotion to the top job seems to be a long shot" When Vice President Biden arrives in South Carolina on Friday to headline a sold-out dinner for state Democrats, here's what you can expect to go down: Biden will stoke speculation that he wants to run for president in 2016 by pressing the flesh in the first-in-the-South primary state. LINK

IMMIGRATION REFORM Bloomberg's Lisa Lerer and Nacha Cattan: " Obama's Mexico Trip Ties Immigration Debate to Economy" President Barack Obama arrived in Mexico today with a message that ties the immigration debate in the U.S. to economic growth on both sides of the border. In his discussions with Mexican President Enrique Pena Nieto, Obama also will be conscious of his audience back home, where Congress next week resumes negotiating possible changes to immigration law. LINK

GUN CONTROL The Washington Times' David Sherfinski: " Eric Holder to Kansas governor: New state gun law unconstitutional " A new law in Kansas that prevents government agents from enforcing federal gun laws in the state is unconstitutional, Attorney General Eric H. Holder said. "In purporting to override federal law and to criminalize the official acts of federal officers, [the law] directly conflicts with federal law and is therefore unconstitutional," Mr. Holder wrote to Gov. Sam Brownback in a letter dated April 26. LINK

SYRIA The Hill's Justin Sink and Jeremy Herb: " Obama says US is 'looking at all options,' could arm Syrian rebels" President Obama said Thursday that the United States was "looking at all options" in Syria, hours after Defense Secretary Chuck Hagel said the administration was reconsidering its opposition to arming rebels in the country. "As we've seen evidence of further bloodshed, potential use of chemical weapons … what I've said is we're going to look at all options," Obama said at a press conference in Mexico City. LINK

ECONOMY The Los Angeles Times' Chris Megerian: " California tax revenue yields multibillion-dollar surplus" California has been flooded with revenue this tax season and is on track to finish the fiscal year with a surplus of billions of dollars, according to officials. State coffers contain about $4.5 billion more than expected in personal income tax payments. Nearly $2.8 billion of it arrived April 17, the third-highest single-day collection in California history, according to government figures. LINK

ABC NEWS VIDEO "Gun Vote, Newtown Families, Follow Senators Home" LINK

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