DOVER — Majority Leader Rep. Valerie Longhurst, D-Bear, plans to file legislation that would eliminate a provision allowing gun sellers to proceed with a sale if the dealer does not receive notice from the FBI within three days. The proposal will have legs in the Democratic-held General Assembly, but it is also sure to face opposition from Republicans and gun-rights groups.

The law governing firearm sales is a federal one, but some states have ended what Rep. Longhurst referred to as a “loophole” in a letter to the members of Delaware’s congressional delegation.

Every person attempting to buy a firearm must first pass a background check. In Delaware, a gun dealer provides a prospective customer’s information, such as name and address, to the FBI. The agency reviews a database containing criminal information provided by the states, and if no results are returned, the buyer is cleared. If the name is flagged, the purchase is delayed, giving the investigator three business days to conduct further research.

Valerie Longhurst

If a response is not received within three days, the seller is legally allowed to complete the sale, although officials can later determine the buyer violates gun ownership prerequisites. In such cases, the FBI notifies the Bureau of Alcohol, Tobacco, Firearms and Explosives.

In 2014, the FBI informed the bureau of 2,511 instances where an ineligible individual was given a firearm due to the delay.

The vast majority of cases that are denied are done because the would-be buyer has been convicted of a crime with a sentence of more than one year or of a state crime with a punishment of at least two years.

The delays “jeopardize public safety,” Rep. Longhurst said in the letter, citing the 2015 church shooting in Charleston, South Carolina. The alleged gunman, Dylann Roof, purchased a gun after the dealer did not receive a response within three days, although the FBI later said he was eventually found to be ineligible.

In previous years, Rep. Longhurst has successfully sponsored legislation enhancing restrictions both on private firearm sales and on gun control for individuals with mental illnesses.

“If we truly believe, as most Americans do, that any person who seeks to lawfully acquire a firearm must pass a background check before doing so, then this is a common-sense solution — no background check, no gun,” she wrote.

“At least 18 states have addressed this delayed transaction loophole in a manner that reduces the number of prohibited people who are able to purchase firearms, and Delaware absolutely should be one of those states.”

According to the FBI, 91 percent of checks were completed within minutes in 2014.

The three members of Delaware’s congressional delegation, Sens. Tom Carper and Chris Coons and Rep. John Carney, all Democrats, have supported greater gun control efforts in the past. Sen. Coons said Thursday he has many of the same worries Rep. Longhurst expressed in the letter.

“As she rightly points out, we only need to look at last year’s horrific shooting in Charleston, South Carolina, to see the terrible risks of loopholes like this post to our communities,” he said through a spokesman. “There is a recent proposal in the U.S. Senate to close the loophole Rep. Longhurst is concerned by, and I am strongly considering supporting it. I believe that only responsible gun owners should have access to firearms, and that is always my perspective when reviewing gun safety proposals.”

A 2015 poll from YouGov and The Economist reported 69 percent of Americans supported a five-day waiting period.

The General Assembly reconvenes March 8, and once the proposal is introduced, voting is likely to fall along partisan lines.

“The bad guys don’t come in to stores and buy guns that get denied,” Sen. Dave Lawson, R-Marydel, said.

Sen. Lawson, who owned Shooter’s Choice in Dover from 1994 to 2012, remembers only one instance of a gun being recalled while he was in charge. That call came from federal officials at least four months after the transfer, he said.

Many gun laws serve only to restrict constitutional rights, Sen. Lawson said.

While he believes purported weaknesses in the background check system are “overblown,” the Delaware Coalition Against Gun Violence applauded the announcement.

“Unfortunately, we can’t count on Congress to protect our communities from individuals who can still buy guns without a proper background check,” Executive Director George Higgins said in a statement. “If we’re going to vet all gun sales, that has to mean every sale — without exception.”