Obama acknowledges the obvious: He has an opponent

FILE - In this April 10, 2012 file photo, President Barack Obama arrives to speak at Florida Atlantic University in Boca Raton, Fla. Seven months before the election, President Barack Obama is just where he expected to be: Taking on Mitt Romney and targeting him as a wishy-washy protector of the rich. With the election likely to hinge on the economy, Obama is stepping firmly into a contentious race backed by an experienced and well-financed campaign organization. (AP Photo/Carolyn Kaster, File)

WASHINGTON (AP) — President Barack Obama is acknowledging the obvious: The presidential contest is now a two-man race.

In a fundraising appeal to supporters, Obama says "we've got an opponent." While the email doesn't mention Republican Mitt Romney by name, Obama writes that he and his challenger "don't see a lot of things eye to eye."

Putting Obama's personal stamp on Romney's status as the eventual GOP nominee is part of his campaign's effort to have the president engage more directly in his re-election bid now that the race has shifted to the general election.

While Romney has looked increasingly like the Republican nominee for several weeks, GOP contender Rick Santorum's withdrawal from the race earlier this week marked the beginning of the general election in earnest.