WASHINGTON  Fresh off a string of victories in the courts and Congress, the National Rifle Association is flexing political muscle outside its normal domain, with both Democrats and Republicans courting its favor and avoiding its wrath on issues that sometimes seem to have little to do with guns.

The N.R.A., long a powerful lobby on gun rights issues, has in recent months also weighed in on such varied issues as health care, campaign finance, credit card regulations and Supreme Court nominees.

In the health care debate this year, for instance, the N.R.A.’s lobbyists worked with the Senate majority leader, Harry Reid, to include a little-noticed provision banning insurance companies from charging higher premiums for people with guns in their homes.

The N.R.A. worked out a deal last month exempting itself from a proposal requiring groups active in political spending to disclose their financial donors. Its push this spring for greater gun rights in the District of Columbia served to effectively kill a measure  once seemingly assured of passage  to give the district a voting seat in Congress.