Former Rep. Charles Djou (R) is expected to announce this week that he is running for his old seat in Hawaii, setting up a potential rematch with Rep. Colleen Hanabusa (D).

The Djou campaign told supporters about his announcement plans in a Monday morning email, stating that “Hawaii has become isolated in the U.S. House by the lack of bipartisan representation in our Congressional delegation.” Both of Hawaii’s House Members are Democrats.

Djou was elected to the House in May 2010 in a three-way special election against Hanabusa and former Rep. Ed Case, who split the Democratic vote. Djou then lost the seat to Hanabusa by 6 points in November, but he never completely left the political scene.

Djou has stepped up his outreach efforts in recent weeks. On July 28, he published an editorial in the Hawaii Reporter that knocked the state’s one-party Congressional delegation, then appeared to lean toward a House run in interviews with a handful of news outlets.

Some Democrats believe Djou is counting on Hanabusa to run for the Senate, with an open seat giving him a better chance of returning to Capitol Hill. But according to a source close to Hanabusa, she remains undecided about a Senate bid.

A proposed redistricting map currently under public review could give Djou a small boost. That plan would add to the 1st district the only state House district that voted last year for GOP gubernatorial nominee Duke Aiona over now-Gov. Neil Abercrombie (D), according to a GOP insider.

Beyond setting up a possible rematch with Hanabusa, Djou’s entrance into the House race could signal that former Gov. Linda Lingle (R) is running for the Senate. Observers believed that Djou, who is close with Lingle, would run for the Senate if she did not. Lingle was supposed to go public with her plans this month, but she recently pushed back the long-awaited announcement to this fall.

Lingle’s entrance would immediately increase the competitiveness of the race for retiring Sen. Daniel Akaka’s (D) seat. The Democratic Senatorial Campaign Committee has already dropped opposition research on her, as a handful of Democrats, including Case and Rep. Mazie Hirono, are already running for the open seat.

But with President Barack Obama at the top of the ticket next year, Republicans know Lingle and Djou would need an extensive amount of split-ticket voters to have any chance of winning. Obama won 72 percent of the vote in Hawaii in the 2008 presidential election, and the Republican wave of 2010 failed to extend across the Pacific Ocean.

The GOP’s hope is that unhappiness with locally elected Democrats will spur voters to opt for down-ticket Republicans after casting their ballot for Obama.