A Democratic tidal wave swept over Nevada on Tuesday, carrying Democrats to Congress, the statehouse and the Clark County Commission in the course of giving a majority of the state's votes to a Democratic presidential candidate for the first time since 1964.

Democratic presidential nominee Barack Obama carried by more than 120,000 votes a state that President Bush won by 20,000 votes four years ago, taking 56 percent of the vote to Republican John McCain's 42 percent on the strength of a grass-roots organization of unprecedented scope, with most precincts reporting late Tuesday.

Three-term Rep. Jon Porter, R-Nev., was ousted by his Democratic challenger, state Sen. Dina Titus, in the suburban 3rd Congressional District, overpowered by the Democratic voter registration trend and the Obama campaign's operation.

Rep. Dean Heller, R-Nev., managed to hang on in the rural and Northern Nevada 2nd Congressional District. But Washoe County, once reliably Republican, turned blue this year, throwing its votes to Obama and Heller's Democratic challenger, Jill Derby.

Democrats took control of the state Senate for the first time since 1991 as two Clark County Republican incumbents, Bob Beers and Joe Heck, succumbed to first-time candidates whose party boosted them with a massive and largely negative independent advertising campaign.

In the Democrat-controlled Assembly, the party lost one seat and picked up two, giving Speaker Barbara Buckley a two-thirds majority in the lower house.

With the gain of two open seats formerly held by Republicans, Democrats will hold every seat on the seven-member Clark County Commission.