WASHINGTON – Republican Rep. Vern Buchanan is fighting off a congressional ethics investigation linked to a former business partner and campaign donations. Democratic Rep. Maxine Waters is battling a charge of impropriety about work she might have done to benefit her husband.

They are among nearly a dozen lawmakers seeking re-election while caught up in federal or congressional investigations that are perfect fodder for campaign foes, rival political committees and free-spending outside groups.

But unlike the headline-grabbing, sex-driven Internet scandals of the past year and a half, these probes center on more complicated financial dealings. Roughly five months to the Nov. 6 elections, they pose less of a threat to political careers, especially for deep-pocketed incumbents or lawmakers in districts that are barely competitive.