Although he is one of the richest Members of Congress and has no well-known challenger yet, Sen. Frank Lautenberg (D) is about to begin an aggressive nationwide fundraising tour, The Philadelphia Inquirer reported Wednesday.

According to the paper, Lautenberg, who is seeking his fifth term — he served from 1983 to 2000 and then won the Garden State’s other Senate seat in 2002 — has scheduled fundraising trips to Austin, Texas, Denver, Los Angeles and Palm Beach, Fla.

Lautenberg, who is 83, started 2007 with more than $1.4 million in his campaign account. But an aide told the Inquirer that the Senator expects to need about $15 million for his re-election.

Republicans have no big-name candidates stepping forward to challenge Lautenberg yet, though they believe U.S. Attorney Chris Christie would be the strongest opponent. Christie, however, seems disinclined to run.

Other potential contenders include state Assemblymen Bill Baroni (R) and Michael Dougherty (R) and real estate developer Anne Evans Estabrook (R), who is close to former Govs. Tom Kean (R) and Christine Todd Whitman (R).

— Josh Kurtz