Nevada Rep. Dean Heller (R-Nev.) , far right, will be the Senate’s newest member, after Gov. Brian Sandoval (R) announced Wednesday that he had picked Heller to replace resigning Sen. John Ensign (R-Nev.). (Charles Dharapak — AP)

Updated at 4:27 p.m.

Nevada Gov. Brian Sandoval (R) announced Wednesday that he will appoint Republican Rep. Dean Heller to fill Sen. John Ensign’s seat.

“Just as Senator John Ensign fought for states’ rights and sound economic policies, Dean will speak out for the concerns of everyday Nevadans,” Sandoval said. “I am confident he will help get Nevada working again.”

Ensign (R) will resign his seat next week amidst an ethics investigation that he said makes it too difficult for him to continue serving. The senator is under investigation for his actions surrounding an affair with a former staffer.

Immediately after Ensign announced his plans last week, Heller became the obvious choice for Sandoval. The third-term congressman and former Nevada Secretary of State is popular in the state and was the presumptive Republican nominee for Ensign’s Senate seat before Ensign announced he would leave the chamber.

There have been some questions about the problems Heller’s appointment would create by forcing a special election for his House seat, though, with state law unclear and Republicans wary of giving Democrats a chance to win the seat.

Some urged Sandoval to appoint a placeholder rather than Heller, but the governor said the state needs an experienced hand like Heller in the Senate. He also said he will work with Secretary of State Ross Miller (D) to make sure that the special election goes off without a hitch.

“Too many important issues face our state and our nation to name a caretaker to this important position; Nevada needs an experienced voice in Washington, D.C.,” Sandoval said.

National Republicans lauded the choice, with Senate campaign chairman John Cornyn (R-Texas) saying “voters throughout Nevada will see firsthand why Dean Heller is the right leader, at the right time, to continue serving them in the U.S. Senate.”

Democrats, meanwhile, accused Heller and Sandoval of engaging in a backroom deal.

“No matter how hard the Republican establishment tries, the election for Nevada’s next senator will be decided at the ballot box next year, not in a smoke filled room,” state party spokesman Zach Hudson said.

Heller will be the Senate’s first appointee since then-West Virginia Gov. Joe Manchin (D) picked Carte Goodwin (D) to replace longtime Sen. Robert C. Byrd (D-W.Va.) a year ago.

Heller will still have to run for a full term in 2012 and the race is expected to be one of the most competitive in the country. Democrats who are running including businessman Byron Georgiou and Rep. Shelley Berkley, who has been endorsed by the Democratic Senatorial Campaign Committee.

It is still unclear whether the special election for Heller’s seat will be an open contest, in which the parties don’t pick their candidates, or would follow a party nomination process.

Former assemblywoman Sharron Angle (R), who lost last year to Senate Majority Leader Harry Reid (D-Nev.), is already running for the seat, but GOP leaders would prefer someone else — Lt. Gov. Brian Krolicki, state party Chairman Mark Amodei, state Sen. Greg Brower and former Navy Cmdr. Kirk Lippold are all either running or considering running — be their candidate, given Angle’s struggles in the 2010 campaign.

On the Democratic side, state Treasurer Kate Marshall is considering a run.

Nevada’s rural 2nd congressional district, which is based in Reno, leans Republican. But it almost went for President Obama in 2008 and Heller faced a difficult race when he won the seat in 2006.

“Special elections are always challenging, and this one is certainly no different,” said Tyler Houlton, a spokesman for the National Republican Congressional Committee.