State Rep. Jackie Walorski (R) has taken the first step toward initiating a 2010 campaign against sophomore Rep. Joe Donnelly (D).

Walorski on Wednesday formed an exploratory committee to run in the 2nd district, which includes South Bend and parts of Elkhart and Kokomo. Exploratory committees almost always blossom into full-fledged official campaigns.

Walorski said in a statement that she was beginning a campaign “because it is increasingly difficult to stand by and watch Washington move down a path that the majority of voters don’t agree with.—

In a recent interview, Walorski expressed opposition to the economic stimulus bill and to cap-and-trade legislation that she said would harm coal-producing Indiana. Donnelly voted for the stimulus plan and voted against the cap-and-trade bill.

Walorski’s candidacy is a signal that the Republicans are looking to contest the 2nd district race more aggressively than they did in 2008, when the GOP struggled to recruit a top candidate and Donnelly crushed little-known businessman Luke Puckett (R) by better than a 2-1 ratio. Donnelly first won by defeating an incumbent in 2006.

The district backed President Barack Obama with 54 percent of the vote last year, giving him large margins in St. Joseph County (South Bend) and in neighboring LaPorte County. Republicans run more strongly in the more rural stretches of the district.