Mitt Romney is to headline the annual convention of the powerful National Rifle Association (NRA), courting gun-rights activists as the fatal shooting of an unarmed black teenager thrust the divisive issue of arms control to the forefront of election-year politics.
The Republican presidential candidate's efforts to assure the NRA that he is on its side - despite having once spoken dismissively of the group - is a reflection of how deeply many US voters believe in their constitutional right to bear arms.
Even President Barack Obama has virtually ignored gun issues during his term despite promises to develop steps on weapons safety. The NRA, nonetheless, considers Mr Obama a foe and plans to mount an aggressive effort against him.
The right to bear arms is guaranteed by the US Constitution, although the country is fiercely divided over how exactly to interpret the Second Amendment that protects gun possession.
The uproar over the shooting of 17-year-old Trayvon Martin at the hands of a neighbourhood watch volunteer in Florida has galvanised pro- and anti-gun control activists alike.
The NRA convention in St Louis, Missouri, provides Mr Romney an opportunity to shore up his credentials with conservatives who have not always trusted his reliability on social issues - including gun control.
Running for the Senate in Massachusetts years ago, Mr Romney once assured voters in a state with strong gun-control laws: "I don't line up with the NRA." Now, the all-but-certain Republican presidential nominee hopes to reap the rewards of the NRA's broad network, which includes more than four million dues-paying members. Mr Romney virtually secured his party's nomination this week when his main rival, Rick Santorum, dropped out of the state-by-state Republican primary race.
Mr Romney leads a list of prominent Republicans who are due to address more than 65,000 convention registrants during a session billed as a "celebration of American values".
His alignment with the NRA comes at a time when gun laws have been under national scrutiny. The NRA was a main backer of Florida's "stand your ground" law, which gives people latitude to use deadly force rather than retreat from danger.
That self-defence law has been much discussed in relation to Trayvon's death in February. After authorities initially declined to arrest him, George Zimmerman was charged on Wednesday with second-degree murder. Zimmerman's lawyer has said the defendant will plead not guilty and invoke the "stand your ground" law.