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 Van Allen, Will Cantine and Jordan Mazza

SYRIA ABC News' Jonathan Karl: Senior Administration Official: ' Very Little Doubt' Assad Regime Behind Alleged Chemical Attack" The White House says there is "very little doubt" that the Assad regime is responsible for the alleged chemical attack in Syria that is said to have taken place earlier this week. "Based on the reported number of victims, reported symptoms of those who were killed or injured, witness accounts, and other facts," a senior administration official tells ABC News, "There is very little doubt at this point that a chemical weapon was used by the Syrian regime against civilians in this incident. LINK

The Wall Street Journal's Adam Entous and Sam Dagher: " U.S. Talks Tough on Syria, Ramps Up Attack Planning" The Obama administration hardened its stance against Syria and stepped up plans for possible military action, dismissing as too late the regime's offer to let United Nations officials inspect areas where the U.S. believes Damascus used chemical weapons last week. The White House and Pentagon signaled the U.S. wasn't backing away from a possible showdown despite apparent efforts by the Syrian government to ease tensions by letting U.N. inspectors visit areas near the capital where hundreds were killed, allegedly by chemical weapons. LINK

The Hill's Julian Pecquet and Ian Swanson: " Obama boxed-in on Syria" A boxed-in President Obama is moving closer to approving air strikes against Syria. More than a year after he first warned the use of chemical weapons would be a "red line," signals emerged Sunday on several fronts that the White House is leaning toward military action. LINK

The New York Times' Scott Shane and Ben Hubbard: " Confident Syria Used Chemical, U.S. Mulls Action" Moving a step closer to possible American military action in Syria, a senior Obama administration official said Sunday that there was "very little doubt" that President Bashar al-Assad's military forces had used chemical weapons against civilians last week and that a Syrian promise to allow United Nations inspectors access to the site was "too late to be credible." The official, in a written statement, said that "based on the reported number of victims, reported symptoms of those who were killed or injured, witness accounts and other facts gathered by open sources, the U.S. intelligence community, and international partners, there is very little doubt at this point that a chemical weapon was used by the Syrian regime against civilians in this incident." LINK

HEALTH CARE The Washington Times' Tom Howell Jr.: " Ted Cruz doubles down on threat to defund Obamacare, proposes alternatives" Sen. Ted Cruz has doubled down on his long shot bid to defund Obamacare, even though Senate Democrats are highly unlikely to approve a short-term spending deal this September that impugns President Obama's signature domestic achievement. In an interview that aired Sunday, the Texas Republican admitted he lacks the votes in the Senate needed to force a government shutdown, but he said a "grass-roots tsunami" of opposition to the Affordable Care Act over the next few weeks could change that. LINK

TEA PARTY The Boston Globe's Noah Bierman: " Democratic strategy promotes Tea Party rivals" Representative Paul C. Broun earned national notoriety by invoking Hitler and Marxism to critique President Obama. He dismissed global warming as "one of the greatest hoaxes perpetrated out of the scientific community." Evolution, the physician has warned, is a lie "straight from the pit of hell." Sounds like a candidate the Democratic Party could never get behind, right? LINK

IMMIGRATION USA Today's Susan Davis and Alan Gomez: " Immigration bill generating little heat in town halls" Republican Rep. Frank LoBiondo represents a South Jersey congressional district with a sizable Hispanic population, farmlands that employ migrant workers, an influential labor union presence and a constituency that voted twice for President Obama. He's precisely the kind of GOP lawmaker immigration advocates said they would target over the August recess, when members of Congress return home for the longest stretch of the year. LINK

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