RACINE — West Virginia Democrats hoped to rally the labor wing of their base Monday at an annual picnic that helps mark the traditional start of the state’s general election season.

Gov. Joe Manchin and U.S. Rep. Nick Rahall were among several party candidates who spoke and mingled at the United Mine Workers union’s 72nd annual Labor Day event in Boone County.

House Speaker Rick Thompson, D-Wayne, and Senate President Earl Ray Tomblin, D-Logan, were also on hand. The two legislators are considered candidates for governor if Manchin wins his U.S. Senate race in November.

The crowd of several hundred proved friendly territory, cheering strongly for the series of Democratic candidate who spoke over the afternoon. Many wore Manchin and Rahall stickers.

‘‘I’m for them both absolutely, 100 percent,’’ said Debbie Gillenwater, 56, of Alum Creek. ‘‘I think Manchin will be good for us in Washington.’’

But union President Cecil Roberts hinted at the mood that faces Democrats nationally when he called it a ‘‘moral obligation’’ for those attending to turn out and vote Nov. 2. In his typical thunderous style, he also urged support for Manchin and Rahall.

With the economy still struggling to recover from recession, the GOP’s base appears far more energized as the general election approaches. A growing roster of analysts see Republicans taking over one or both houses of Congress.

‘‘You have to be on fire for these people, because everything we have is on the line in this election,’’ Roberts shouted.

Roberts earned applause for that line, and for invoking an image of union foe and Massey Energy chief executive Don Blankenship being arrested and thrown in jail. State and federal officials continue to investigate April’s explosion at the Massey-owned Upper Big Branch mine, just 25 miles down the road, which left 29 men dead.

The coal mining disaster, the nation’s worst in 40 years, was a recurring topic at Monday’s picnic. Roberts reminded the crowd that Blankenship is backing Rahall’s Republican opponent, Elliott ‘‘Spike’’ Maynard.

‘‘I don’t think Rahall has any problem at all. He’s done a good job,’’ said Porter Snodgrass, a retired steelworker from Racine.

‘‘He’s been good to Boone County,’’ seconded Teddy Bowles, a retired truck driver from Ashford.

While Rahall enjoys support among some coal operators, others have criticized him for not doing enough to oppose the Obama administration proposals meant to reduce greenhouse gas emissions. West Virginia is the country’s second-largest producer of coal, which releases carbon dioxide when burned.

Seeking an 18th term, Rahall sought to defuse those concerns Monday.

‘‘I’ve spent 34 years defending the industry and the coal miners themselves,’’ the 3rd District Democrat told The Associated Press. ‘‘I ask these newfound people who claim that there’s a war on coal now, ’Where have you been?’’’

Manchin praised coal miners throughout his rally speech, touting the role coal has played in building the country’s industrial and economic might. Nearly halfway through a second term, Manchin called his Senate bid a chance to continue to share West Virginia’s story with a national audience.

‘‘I’m trying to tell them who we are, how we were raised, the character of our people, the strength of our families,’’ Manchin said. ‘‘This little state has given her all... What they need in Washington is a good dose of West Virginia.’’

Manchin, GOP nominee John Raese and the Mountain Party’s Jesse Johnson seek the bulk of what remains of the late Robert C. Byrd’s term. The 92-year-old Democrat died June 28, and next would have gone before voters in 2012.

Republican candidates have spoken at previous Racine picnics, but organizer Teddy Hapney said he never heard back from any for this year’s event.