Rep. Rick Lazio said Tuesday he expects to announce this summer that he will seek the Republican nomination for the Senate seat that Hillary Rodham Clinton is also eyeing.
Lazio will probably face New York Mayor Rudolph Giuliani for the GOP nomination.
"The way you beat Rudy is run as the Republican," the Long Island congressman said, noting the mayor's crossing of party lines in 1994 to endorse Democratic Gov. Mario Cuomo over Republican George Pataki in a race won by Pataki.
Giuliani political adviser Bruce Teitelbaum declined to comment on Lazio's plans. The mayor formed a Senate exploratory committee in April, but has yet to announce his candidacy.
The Senate race is for the seat being vacated next year by Democrat Daniel Patrick Moynihan. Mrs. Clinton plans to form an exploratory committee in early July.
"I go into it as the underdog and I have a keen understanding of what that means," Lazio, 41, said. "It's a David-and-Goliath race against two titans."
Lazio said he will campaign on the theme that both the First Lady and the mayor want to use the Senate seat as a stepping stone to higher office and that the blunt Giuliani has the wrong temperament for the Senate.
"I will be making an announcement sometime in the summer," Lazio said.
Lazio is assistant majority leader in the House but is little-known off Long Island. He has been crisscrossing the state in recent months, courting Republicans.