LAFAYETTE, La. (AP) — Sen. Mary Landrieu is a Democrat from a powerful political family. But her three previous victories have depended on just enough support from independents and Republicans.

Replicating that formula to win a fourth term this fall may depend on what matters more to voters: her influence as a veteran senator and new chairwoman of the Senate's energy committee or her unapologetic vote for President Barack Obama's health care overhaul.

Some Republicans in the state's oil and gas industry say her chairmanship means too much to justify a change. But others who've supported her before say it's time to back the leading Republican challenger, Baton Rouge congressman Bill Cassidy.

Landrieu, Cassidy and others will be on a single primary ballot in November, with a runoff, if necessary, in December.

More From News Radio 710 KEEL