Three of the region’s four senators back a bill that would allow gun owners to carry concealed weapons across state lines as long as they have a valid concealed weapons permit from their own states.

   The measure favored by Republicans Pat Roberts and Sam Brownback of Kansas and Kit Bond of Missouri would require gun owners to follow the concealed-carry laws in the state they’re in.

   “This is a common sense bill that will make it easier for the 48 states with similar conceal carry laws to offer reciprocity and make it easier for Americans who are inclined to exercise their Second Amendment rights without needing a permit in every other state,” said Brownback spokesman Brian Hart.

   Only Wisconsin and Illinois would be excluded since they don’t have “concealed carry” laws.

    Missouri’s other senator, Democrat Claire McCaskill, opposes the bill.

   The effect of the bill, authored by Republican Sen. John Thune of South Dakota, would be to force some states to allow less stringent standards for concealed weapons than they prefer for their own states.

    In other words, people with concealed carry permits from states with weak criteria for obtaining them would be allowed to carry concealed weapons in states where the criteria is tougher.

   For instance, more than 30 states, including Missouri, prevent alcohol abusers from obtaining conceal carry permits, according to a letter signed by 400 mayors opposed to the Thune legislation.

    The mayors of Kansas City, St. Louis and Creve Coeur in Missouri, and Kansas City, Lake Quivira and Lansing in Kansas were among the signers.

   The group also noted that more than half of the states refuse permits to people convicted of misdemeanor violence, and also require applicants to take a gun safety program. Both Missouri and Kansas are among them.

    “This is a reckless amendment that would force states from coast to coast to comply with the weakest concealed carry laws,” Democratic Sen. Frank Lautenberg of New Jersey said on the Senate floor.

    The National Rifle Association supports the Thune bill. The Hill newspaper, which covers Congress, printed a letter from the NRA to lawmakers urging them to vote for it.

    “Expanding right-to-carry will enhance public safety, and certainly poses no threat to the public,” the group wrote. “Criminals are deterred from attempting crimes when they know or suspect that their prospective victims are armed.”

  Thune offered the legislation as an amendment to the Defense bill that the Senate has been debating this week. A vote on the concealed carry measure is expected Wednesday.