CALIFORNIA ELECTIONS / U.S. SENATE : Feinstein Focuses on Crackdown at the Border : After declaring her opposition to Prop. 187, she says she believes the immigration battle will be won or lost at the points of illegal entry.

This is the nation’s most porous section of international border, and in the pitch dark on Saturday night, U.S. Sen. Dianne Feinstein watched as an agent demonstrated how a brand-new night-vision scope she voted to fund in Washington this year is changing the battle against illegal immigration.

One day after she announced her opposition to Proposition 187, the ballot measure cutting education and health benefits to illegal immigrants, Feinstein shifted her attention to the border, where federal officials say millions of dollars for new trucks, computers, electronic detection equipment and personnel is helping reduce the flow of illegal crossings.

Just three weeks ago, federal officials launched an ambitious border crackdown called Operation Gatekeeper, which quadrupled the night assignment of guards to the nation’s busiest five-mile stretch of border.

The operation is so new that its successes have not been advertised. But with a close election just two weeks away, good news is not something for which Feinstein can wait.

“What I’ve been trying to do for two years now, through appropriations, is get the Border Patrol the tools they need to do their job,” Feinstein said at an 11 p.m. press conference outside the Imperial Beach Border Patrol station. “Then we’ll see if the job can get done. I believe it can.”

Illegal immigration is such a major issue in California, Feinstein said, that she could lose her bid for reelection because she opposes Proposition 187 at a time when the measure shows strong support in opinion polls.

The senator said, however, that she believes the battle over illegal immigration will be won or lost at the border. Proposition 187, she argued, is unconstitutional and it will not work.

“Does anybody think that this proposition puts one new border guard on the border?” she asked at a fund-raiser Saturday evening in San Jose, shortly before flying south on a campaign jet. “Do you think it sends back one illegal immigrant? What it does is it strikes out at children. What it does is put into every teacher and every doctor a responsibility of being an immigration agent.”

Feinstein’s Republican challenger, Rep. Mike Huffington of Santa Barbara, contends that providing public school classes and health care to illegal immigrants is tantamount to a reward for lawbreakers. And according to polls, most Californians agree.

As a result, Feinstein’s campaign has been briefly sidetracked as it has been forced to quickly defend a politically unpopular position in the final days of a close election. Her strategists expect that it will hurt the campaign--the only question is how much.

With Saturday’s tour, Feinstein was able to demonstrate the changes she thinks are more effective than Proposition 187 in addressing the problems caused by illegal immigration.

Federal officials proudly showed the senator the busiest spots along the border, where hundreds of people used to gather before crossing the mile-wide stretch of dry riverbed between the lights of Tijuana and neighborhoods of San Ysidro. This time there were only handfuls of people.

Ann Summers, spokeswoman for the border guard at Imperial Beach, said it is still early to tell, but officials estimate a 60% reduction in traffic through the area.

Before Operation Gatekeeper, Summers said, between 200 and 300 people were apprehended each night at the Imperial Beach station. When the new program began Oct. 1, apprehensions jumped to more than 800 and have dropped sharply since.

At the same time, the border stations further east have reported as much as three times the normal level of traffic, indicating that the crackdown on the beach has forced border crossers to try elsewhere.

But Summers said that is part of the federal strategy, since at the more rural, eastern locations, it takes about three hours for border crossers to reach a U.S. neighborhood where they can hide, compared to just minutes along the beach.

“For us, the difference is incredible, it really is,” Summers said. “It is incredible because it is just so quiet out there. Before, on any other given night, you would have seen a lot more people.”

In Feinstein’s first stop on the tour, her fourth visit to the border since taking office, she saw a demonstration of a new computerized booking operation.

In a room where detainees’ names used to be recorded in logs with paper and pencil, the job was now done at 16 hastily made plywood computer stations. The computers also allowed agents, for the first time, to take fingerprints electronically and instantly search criminal records for a match.

The headquarters also includes a control room where hundreds of seismic sensors planted in the ground are monitored.

Later, riding in a four-wheel-drive station wagon through the rugged terrain, Feinstein passed some of the shiny new Chevy Blazers that agents use to patrol the area.

In the past, Summers said, about 20 agents would monitor the five-mile stretch of border. Now, there are more than 80 deployed at one time.

More are expected, she said. Congress has already funded 1,300 additional border agents, with most of the deployment assigned to Southern California. So far, Summers said, about 74 new agents have recently taken positions in the San Diego area.

But the reinforcements, combined with the reassignment of some office staff to the field, have already made a difference, she said.

Previously, agents were often “pinned down” as they parked in front of a crowd that was waiting for them to leave before it crossed. Then, she said, the alarms set off by seismic sensors were often ignored because agents were unavailable.

The five-mile stretch of border is also watched now by three night-vision scopes, compared to just one previously. Some are mounted on tripods. The $156,000 model Feinstein viewed had a turret-mounted camera on top of a four-wheel-drive vehicle that was monitored by a video screen in the dashboard.

The scope, purchased from the Defense Department, could spot a person crossing in the dark more than three miles away.

“The border, I can tell you, is just night-and-day different,” Feinstein said after her tour. “The operation is very dramatic and very much improved.”