Embattled Nevada Gov. Jim Gibbon’s road to re-election just got even tougher. Former state Sen. Joe Heck, who lost a tight race for re-election himself in 2008, announced Monday that he is running for the post in 2010. Heck’s decision was first reported Friday by Las Vegas Sun columnist Jon Ralston.

Heck is the second Republican to mount a primary challenge against Gibbons — North Las Vegas Mayor Mike Montandon has already declared his candidacy.

Heck, a doctor by training, represented Clark County’s 5th District from 2004 to 2008 and remains popular in the state’s Republican circles. His challenge to Gibbons is supported by many in the party establishment, who worry the incumbent, weakened by scandals and poor relations with the state legislature, is a ripe target for Democrats.