ROGERS, Ark.—John McCain on Friday said he considers Arkansas a key state in his bid for the presidency and said he plans to campaign hard in the state—even reaching out to what he called “Clinton Democrats.”

“I think Arkansas will be a swing state and I think it will be a real challenge,” the likely Republican presidential nominee told reporters before a fundraiser in Republican-heavy northwest Arkansas. “We intend to be here and campaign hard here.”

For his second visit to Arkansas since March, McCain chose a region that’s been reliably Republican despite Democratic Party gains statewide. It’s also an area that George W. Bush used as a backdrop for an election-eve visit before winning the state in 2000.

McCain used the visit to criticize likely Democratic nominee Barack Obama for co-sponsoring the Employee Free Choice Act, which would allow labor organizations to unionize workplaces without secret-ballot elections. Bentonville-based Wal Mart Stores Inc.—which has rigorously resisted being unionized—also opposes the measure.

“The fact is (Obama) supports that, and I think that could be dangerous to the essence of democracy,” McCain said during a fundraiser Friday night.

The Arizona senator headlined a $500-a-person fundraiser Friday night in Rogers, along with his one-time rival for the GOP nomination, former Gov. Mike Huckabee. McCain said before the event that he hoped to appeal to moderates and independents in the state.

“We need to reach out to independents, old and new, what we used to call Reagan Democrats and some you might call Clinton Democrats as well,” McCain said. Arkansas Democrats overwhelmingly supported former Arkansas first lady Hillary Rodham Clinton in the February presidential primary.

McCain told about 200 supporters at the fundraiser that he believes he has a “headwind” in the state. He was joined on stage by Mike and Janet Huckabee, along with Rep. John Boozman and his wife, Cathy.

“If John Boozman and Mike Huckabee can transfer some of their popularity to my campaign, then thank God for them,” McCain said during the fundraiser. “We’ve got a lot of work to do in this campaign and I’m the underdog, my friends.”

Friday’s fundraiser marked the second visit the state by McCain since he secured enough delegates to clinch the nomination in March and his first to northwest Arkansas. The region is considered the Republican heartland in a state where Democrats swept all the top state offices in the 2006 election, and added to their large majority in the Legislature.

McCain offered praise for Huckabee but wouldn’t say if he was considering the former governor for the second spot on the GOP ticket. But he did say he believed the governor had earned a future role nationally in the party.

He also said the two bonded during the presidential campaign, when political observers had written off their chances.

“There was a time before this time a year ago where most political pundits didn’t think the former governor from a small Southern state nor this guy from Arizona whose campaign had imploded had much of a chance,” McCain said.

Huckabee later returned the compliment, but joked during the fundraiser that “I want you to know with the utmost sincerity he really was my second choice to be president of the United States.”

McCain’s candidacy has raised the hopes of state Republican leaders looking for encouragement. Recent polling and the exit of Clinton from the Democratic presidential race have also raised those hopes.

In a March poll by the University of Central Arkansas, McCain led in the state in a matchup against Barack Obama, the presumptive Democratic nominee, with 43 percent saying they would support McCain and 27 percent supporting Obama. In that survey, 26 percent of likely voters were undecided.

Arkansas went to George W. Bush in the past two presidential elections.

McCain finished second to Huckabee in the state’s Feb. 5 presidential primary, and the former governor dropped out of the race the following month. Obama also finished second in his party’s primary in the state, behind Clinton.