SAN DIEGO -- Republican 50th Congressional District candidate Brian Bilbray avoided what could have proven a thorny encounter Wednesday, after U.S. Sen. John McCain pulled out of a campaign fundraiser for Bilbray on the eve of the event.

Adding to the dicey nature of 11th hour cancellation, Bilbray adamantly opposes an immigration reform measure McCain helped craft -- a bill that is supported by Francine Busby, Bilbray's Democratic opponent in the race to temporarily fill the seat formerly held by Randy "Duke" Cunningham.

McCain skipped the $250-a-plate breakfast at a San Diego hotel, because of "differences" over a solution to illegal immigration, Bilbray said Wednesday.

The focus of many of the comments made at Bilbray's fundraiser centered on the issue -- one that has been the centerpiece of his campaign.

Meanwhile, Busby held a similar fundraising event later in the day, featuring House Minority leader Nancy Pelosi, D-San Francisco, as guest speaker. But at Busby's event, ethics reform in Washington -- the main plank in Busby's platform --- topped the agenda.

Arizona senator and 2008 presidential hopeful McCain helped craft a version of a bill that was approved last week by the U.S. Senate. A provision in that bill would create a guest-worker program and allow millions of illegal immigrants a pathway to legalization.

Bilbray opposes the bill and wants to see a competing House bill become law -- a bill that does not include a guest-worker program nor a mechanism for legalizing some of the estimated 11 million to 12 million illegal immigrants who are living in the United States.

He said he told McCain's staff that McCain is "dead wrong on the amnesty issue," and a number of the people who attended the Wednesday breakfast were prepared to tell the senator the same thing, Bilbray said.

Had McCain come, Bilbray said, it would have put him in the position of "maybe having to protect the senator from reaction here in San Diego."

Officials with the senator's office could not be reached for comment Wednesday.

Filling in for McCain at the event, which drew about 130 supporters, was U.S. Rep. David Dreier, R-San Dimas, who serves as chairman of the House Rules Committee. Also stumping for Bilbray was U.S. Rep. Duncan Hunter, chairman of the powerful House Armed Services Committee.

Both members praised Bilbray as the man they hope to see at their side in the House after the election, to help them push forward stronger immigration reform legislation and increase the nation's security.

"The election of Brian Bilbray is very important for the state and the nation," Dreier said.

He said that with Bilbray's help, he hopes to see included in the House version of the immigration bill a provision for a high-tech Social Security card that anyone seeking a new job would have to present to a prospective employer.

Employers would have to check that card against a national database to make sure the card holder is in the country legally and employers who did not do so could face heavy fines and possible imprisonment, said Dreier who proposed the idea last year.

The House and Senate bills will now go before a conference committee composed of members from both chambers to try and work out a consensus version of the legislation.

Dreier also alluded to the high stakes of the June 6 runoff in which Bilbray and Busby are the front-runners. The race between the two is neck and neck, according to a recent automated poll of likely voters that showed 45 percent of respondents saying they would vote for Bilbray and 45 percent for Busby.

The closeness of the contest has come as a surprise to some, since the 50th District has 157,000 registered Republicans to 105,000 registered Democrats and the seat has long been considered a safe one for the GOP.

In a sign of the concerns of both parties over an election that many have called a bellwether for congressional elections across the nation this fall, the national arms of the Democratic and Republican parties have sunk a combined total of more than $2 million into campaign advertising on local TV stations since April 11.

"The eyes of the nation are on this race," Dreier said. "People are saying what happens next Tuesday will play a big role in what happens in November."

But Dreier and Hunter weren't the only Washington big guns to come to town Wednesday. House Minority Leader Pelosi also stumped for Busby at a Wednesday evening fundraiser held at a private home in La Jolla.

Pelosi told a group of about 150 supporters, who made donations to Busby's campaign of at least $100, that electing Busby is the first step toward Democrats regaining control of the House.

If that happens, she pledged that a Democratic House will initiate an era of "pay as you go" and will "stop heaping mountains of debt on our children." Echoing Busby's calls to clean up Washington, Pelosi said that Tuesday's election is about integrity.

"Her election will send a message to the American people to push aside the old -- it's time for the new."

Unlike the Bilbray event, where the No. 1 topic was illegal immigration, barely a mention was made of the issue at the Busby event.

Commenting on conservative Republicans' intense focus on the issue, a Busby supporter said he believes that was a strategic decision on the part of the GOP. "The Republican Party has put it on the front page to distract from the war in Iraq," said San Diego resident John Evans, 52.

San Diego County Republican Party Finance Chairman Tony Krvaric was standing outside the Busby fundraiser just before it started.

Saying he came to scout out what the opposition was up to, Krvaric said North County voters' views are totally incompatible "with the San Francisco liberal policies of Nancy Pelosi -- Busby is aligning herself with the most liberal faction of the Democratic left."

Contact staff writer William Finn Bennett at (760) 740-5426 or wbennett@nctimes.com.