Oregon Democratic Rep. Darlene Hooley’s announcement late last week that she plans to retire at the end of the year gave House GOP political strategists some rare good news.

It came after a rash of similar Republican announcements and creates the first truly competitive open-seat race in a Democratic-held House district this cycle.

Both Democratic and Republican statewide candidates have won the Willamette Valley-based 5th district in recent elections, and control of the seat swung back and forth four times in the 1980s and 1990s. Republicans are certain to make a play for it now.

But while acknowledging that they’ll have to work hard to defend the seat, Democrats believe they should have the upper hand in November, given the fact that the district has turned more suburban in the past few years. They also noted that Hooley’s victory margin grew in the past few cycles, despite the fact that President Bush won the district by 1 point in both the 2000 and 2004 White House elections.

“We are confident that a Democrat will win this seat and continue to work to change the direction of the country,” said Democratic Congressional Campaign Committee Chairman Chris Van Hollen (Md.).

Mike Erickson, the wealthy Republican businessman who lost to Hooley by 11 points in 2006, already was seeking a rematch. Even before the Congresswoman dropped out of the race, GOP operatives were expressing confidence that he would be a more savvy, sure-footed candidate this time. He spent almost $1.6 million of his own money on the losing effort in the previous cycle and finished 2007 with about $131,000 in his campaign account.

Republican sources said late last week that Erickson was prepared to immediately drop more than $300,000 of his own money into his campaign coffers in the wake of Hooley’s announcement — both as a signal to national GOP leaders and donors that he was serious about winning the seat, and also to prevent other potential Republican candidates from getting into the race.

State Rep. Brian Boquist, who was the Republican nominee against Hooley in 2000 and 2002, was reportedly thinking about running, and Kevin Mannix, the wealthy former state GOP chairman, also is seen as a possibility.

The list of possible Democratic candidates as of late Friday had an “All in the Family” feel. It included former Monmouth Mayor Paul Evans, an Iraq War veteran who is married to Hooley’s chief of staff and reportedly already was talking to potential campaign consultants last week; Clackamas County Commissioner Martha Schrader; and her husband, state Sen. Kurt Schrader.

The filing deadline for Oregon candidates is March 11 and the primary is on May 20.

Hooley, who is 68, said she decided to leave Congress because she was tired of the constant travel and the pressure to raise enormous sums of money. Although she spent 32 years in elective office — including stints as a city councilwoman, county commissioner and state legislator — she called her six terms in Congress “my greatest honor and privilege.”

Hooley, who is known as a strong consumer advocate and has fought to preserve Oregon’s controversial assisted suicide law, said she wants to stay in public service but is not sure what she’ll do next. She serves on the Energy and Commerce, Science and Technology, and Budget committees, and her Energy slot in particular will be coveted by her colleagues.

David M. Drucker contributed to this report.