Gun Owners of America, with its war chest, membership, and lobbying strength dwarfed by the National Rifle Association, is emerging as an influential force as a series of gun control measures heads to the Senate floor, reports the New York Times. The group has been successful in both freezing senators, particularly Republicans, who have appeared to be on the fence about supporting bills to expand background checks and increase penalties for illegal gun purchases, and empowering those who have a strong gun rights background. “They are strong defenders of the Second Amendment,” said Sen. Ted Cruz (R-TX), who got donations from the group during his primary campaign and is its key ally in the Senate. Gun Owners of America's revenue in 2011 was less than $2 million, compared with the NRA's $220 million. The group spent $1.3 million last year to lobby Congress, while the NRA spent nearly $3 million. Like many grass-roots groups, it is loud. Its members pepper Republican lawmakers with calls. In Republican primaries, the group supports candidates that hew to its message, and it rates floor votes with criteria far tougher than the NRA's. Senator Max Baucus of Montana, one of the few Democrats to earn an A from the NRA, has a D-minus from Gun Owners of America.