ABC News’ Matthew Jaffe reports:
Sen. John Ensign, R-NV, plans to announce at a news conference later today in Nevada that he will not run for re-election, a Republican source tells ABC News.
Ensign was facing an uphill campaign after being dogged by controversy in recent years, so his decision to leave the Senate will come as welcome news to the GOP since his re-election prospects appeared poor.
Last month the Senate Ethics Committee appointed a special counsel to handle an investigation into Ensign after allegations that the lawmaker violated Senate rules and federal law. Ensign had an affair with a former campaign aide who was married to his deputy chief of staff. Last year the Justice Department scrapped a criminal investigation into the Ensign matter, but the Senate Ethics probe remains ongoing.
Ensign will now become the third GOP senator to leave the Senate, after Jon Kyl of Arizona and Kay Bailey Hutchison of Texas.
Across the aisle five Democrats have decided not to run for re-election in 2012, a group that includes Kent Conrad of North Dakota, Joe Lieberman of Connecticut, Jeff Bingaman of New Mexico, Daniel Akaka of Hawaii and Jim Webb of Virginia.
Republicans need a net gain of four seats to wrest control of the Senate from Democrats. However Democrats have to defend 23 Senate seats compared to only 10 for the GOP.
Ensign plans to make the announcement at a press conference at the Lloyd G. George Federal Courthouse in Las Vegas at noon Pacific standard time.