RICHMOND -- Standing with parents of Virginia Tech shooting victims and law enforcement officials, Gov. Tim Kaine on Tuesday urged state lawmakers to require criminal background checks for all firearms purchases made at gun shows.

The governor's proposal would eliminate the so-called "gun show loophole" that allows unlicensed vendors to sell firearms without conducting computerized criminal records checks on buyers. A 1991 state law requiring instant background checks applies only to licensed dealers.

Kaine's appeal, coming on the eve of the General Assembly session, launched what could become an intense debate over gun control. But the governor faces a tough fight, including opposition from some prominent members of his own party.

In the aftermath of the Tech shootings, Kaine said, the state must do more to keep guns from convicted felons and individuals with dangerous mental illnesses.

"If by doing this, we can keep one family from having to go through what these families have suffered, it will be the best thing that the legislature will do this year," Kaine said in a news conference at Virginia State Police headquarters.

Several parents of students who were killed or injured in the April 16 shootings joined the governor in a show of support for the legislation. Joseph Samaha, whose daughter Reema died in the shooting rampage, said he intends to stay involved in efforts to pass Kaine's legislation, and said the issue transcends partisan, regional and cultural differences.

Seung-Hui Cho, the Tech student who killed 32 people and himself, was able to purchase firearms from licensed dealers because authorities had not entered information about his mental illness into the federal database used for instant records checks. Two weeks after the shootings, Kaine issued an executive order requiring the names of all people involuntarily committed to receive mental health treatment to be entered into the database. The General Assembly likely will pass legislation making Kaine's order permanent.

But a panel that investigated the Tech shootings noted that Cho could have avoided a background check by purchasing weapons from an unlicensed seller at a gun show. It recommended closing the gun show loophole.

Samaha said it's logical to assume Cho would have bought guns from an unlicensed seller if he had problems with a background check.

"Let's connect the dots," he said.

State Sen. Henry Marsh, D-Richmond, will sponsor the legislation, despite having failed in previous attempts to pass such as a bill.

"It's a no-brainer; it's an idea whose time has come," said Marsh, who will be chairman of the Senate Courts of Justice Committee.

Kaine's proposals would not affect private sales that occur away from gun shows.

"It's not about interrupting just good old-fashioned horse trading," said Col. Steve Flaherty, the superintendent of the state police. "It's not about going after people who buy, sell or trade guns with their family, with their friends, with their hunting buddies and this sort of thing."

Mike White of Smithfield, Va., the father of slain student Nicole White, said Kaine's proposals only would affect "those who really should not have a gun to begin with."

"As a gun owner myself and a previously avid hunter, I believe this bill is a healthy compromise that will bring safety to our families," White said. "Of course, for our families, that's already passed."

Kaine acknowledged that he faces a challenge winning support for a proposal that has failed in previous legislative sessions. The governor could even face opposition from prominent lawmakers in his own party, including House Minority Leader Ward Armstrong, D-Henry County, and state Sen. Creigh Deeds, D-Bath County.

Armstrong said last month that he opposes changing the law. Deeds, who has announced plans to run for governor in 2009, said he has opposed similar legislation in the past and has not changed his opinion. And, he added, "the so-called gun show loophole had absolutely nothing to do with the tragedy that occurred at Virginia Tech."

Gun rights advocates also hope to defeat the measure. Philip Van Cleave, the president of the Virginia Citizens Defense League, said Kaine's proposal would have "little or no impact" on keeping guns away from criminals. He warned that changing the law could be a first step in a move to undermine private, one-on-one sales that occur away from gun shows.

"A loophole implies that when legislators wrote the law, they really didn't think about this," Van Cleave said. "That's not true."

Attorney General Bob McDonnell, a former legislator, said the General Assembly would have closed the loophole "if there was a clear and present danger created by transactions in the parking lot at gun shows."

"We're not aware of any data ... that any reliable law enforcement agencies have that would suggest this is creating a public safety problem," McDonnell said.

Kaine said his proposal will inconvenience only people who are barred by law from owning a gun.

"We need to close this last door, this significant loophole, that provides an end run which would enable criminals and other dangerous individuals to find easy access to guns to do others harm," the governor said.