"Perfect security is impossible," he wrote in his letter. "However, the limited resources of the TSA must be focused on the greatest threats and on the highest probability of preventing an attack.

"That is not achieved by continuing the ban of these minuscule knives which are tools carried by millions of Americans."

Kristine Michalson, Salmon's communications director, told The Hill that Salmon got involved in the issue after attending the grand opening of a small custom knife shop run by a disabled veteran in Arizona.

Salmon's letter agrees with the logic of the TSA, which has proposed allowing knives to be included in carry-on bags if they don't lock, have blades that are no longer than 2.36 inches, and are less than a half-inch wide. He said the new policy must be seen in the perspective of TSA's 2005 policy change that allowed short scissors to be brought onboard.

But in March, TSA's proposed policy prompted 133 members of the House to urge TSA to reverse this policy. Their letter to TSA argued that the policy change makes no sense in light of the September 2001 terrorist attacks, in which hijackers used pocket knives to commandeer aircraft.

In addition, Rep. Ed MarkeyEdward (Ed) John MarkeyOPEC and Russia may raise oil output under pressure from Trump Tech companies scramble as sweeping data rules take effect Fixing a colossal mistake in the tax bill MORE (D-Mass.) has proposed the No Knives Act, H.R. 1093, which would reverse TSA's decision. Markey's bill has 16 co-sponsors, including one Republican, Rep. Michael Grimm (R-N.Y.).

"The attacks on September 11, 2001, demonstrated that in the confined environment of an airplane, even a small blade in the hands of a terrorist can lead to disaster," Markey wrote in a March letter to TSA.

Salmon's "dear colleague" letter called on members to oppose Markey's bill, which he called an "ill-conceived attempt" to thwart the TSA rule and micromanage the agency.

"H.R. 1093 is an overreaction to this commonsense change by the TSA," Salmon wrote. "It micromanages the TSA instead of leaving them to do its job."