The interaction comes as the Bush administration is proposing a $4 million project to build fixed facilities within 100 miles of the Canadian border to conduct random vehicle checks for illegal immigrants, drugs and weapons, according to Leahy.
"So what you're saying is in a little state like mine everyone should be stopped going down that interstate, no matter whether they're going to visit a sick relative at the VA hospital?" Leahy prodded Chertoff in a Judiciary Committee hearing.
"We're all sort of presumed guilty until proven innocent," the Vermont Democrat added. "It sounds like Big Brother gone awry."
Chertoff said, "Here's the bottom line. Having checkpoints make sense."
He said drug dealers and child molesters have been captured at similar checkpoints.
A similar, though temporary, checkpoint was maintained for 18 months along I-91 near Hartford, Vt., before closing in May 2005, according to Leahy.
But he says it's an inconvenience for Vermonters miles away from the border they may never cross.
Leahy, for instance, was stopped at a different checkpoint in New York and told to get out his car, he recalled at a separate hearing last month. When he asked the Border Patrol agent under whose authority he was working, the agent pointed to his gun.
"That's all the authority I need," the agent said, according to Leahy.
Interior checkpoints are used mostly in the south as a second layer of security to apprehend terrorists, illegal immigrants and drug smugglers who evaded detection at the point of entry. But there is debate about the effectiveness of permanent facilities versus tactical checkpoints, which are moved frequently.
"We have dozens and dozens of roads you can take from the Canadian border to get down to either New York or Massachusetts from Canada," Leahy said Wednesday, adding dryly, "Why don't you just put roadblocks on every one of them and federalize Vermont?"
Leahy then leaned into his microphone and whispered conspiratorially: "We've had Canadians come up to my house in Vermont. Some of them are related to my wife."
Chertoff responded, "That's great. But I'm not sure what your point is, Mr. Chairman."
But by then Leahy was done jesting with Chertoff.
"I think you understand my point," Leahy said.