Sen. Dianne Feinstein is trying to block votes on bills that would require a state to honor concealed gun permits from other states.
The California Democrat wrote Majority Leader Harry Reid and Judiciary Committee Chairman Patrick Leahy, requesting that no votes be scheduled on two concealed weapons "reciprocity" bills. There was no immediate response from Reid, D-Nev., or Leahy, D-Vt., to the letter dated April 17.
The National Rifle Association said it would not be deterred in efforts to pass reciprocity legislation.
"We have to work harder to get 60 votes, and we're prepared to do that," NRA spokesman Andrew Arulanandam said, referring to the number of senators needed to end a filibuster.
Feinstein wrote, "These dangerous bills ... would undermine states' rights by forcing nearly every state to accept the concealed carry permits issued by other states, even if the permit holder could not qualify for a permit i the state to which he is traveling."
She said major law enforcement agencies opposed the legislation.
Feinstein said the bills present a special problem for women who are domestic violence victims.
"Imagine that a man who has been convicted of a domestic violence crime against a woman he had been dating seeks _ and obtains _ a permit to carry a concealed firearm from his state of residence," she wrote. "Under the concealed carry reciprocity bills, he could legally travel across state lines and confront his former girlfriend ..."
She pointed out that state laws vary widely in their requirements for individuals to possess firearms or obtain concealed weapons permits.
Some states issue permits to people with violent misdemeanor criminal convictions, do not require firearms safety training, and do not grant discretion to law enforcement.
Law enforcement officers, she added, could face potentially life-threatening situations. She said it often is impossible for an officer to determine if an out-of-state concealed carry permit furnished during a traffic stop is valid. She said most states do not enter permit information into the primary database used by officers when conducting a stop.
The Republican-controlled House passed a similar measure last year.