Barack Obama will focus on the economy in his stops in Virginia, his fourth visit to the state since locking up the Democratic nomination.

Aiming to pick off a swing state and perhaps pick up a vice-presidential running mate, Barack Obama this morning opens a two-day swing across Virginia that includes a stop tomorrow in suburban Richmond.

Ahead of the visit, the focus of which will be the economy, top Republicans threw out the un-welcome mat for the all-but-official Democratic presidential nominee.

Sen. John W. Warner, R-Va., and Rep. Thomas M. Davis III, R-11th, declared the state for John McCain, the GOP's presumed nominee, but said that choosing Gov. Timothy M. Kaine for vice president could tip Virginia to the Democrats for the first time since 1964.

Obama plans visits today to Martinsville, a textile-and-furniture hub in the western part of south-central Virginia that has lost thousands of jobs to foreign manufacturers, and Lynchburg, the hilly home of the late Rev. Jerry Falwell's conservative religious empire.

Obama, accompanied by Kaine, will appear tomorrow at John Tyler Community College in Chester, a GOP area where there was a surprisingly heavy vote for Obama in the Democratic primary in February. Obama wraps up tomorrow evening in the fast-growing Hampton Roads city of Chesapeake.

The Martinsville and Chester give-and-takes are invitation-only. Tickets are no longer available to the Lynchburg event. The Chesapeake session also requires tickets but is first-come, first-served.

This will be Obama's fourth visit to Virginia since wrapping up the nomination. McCain has made one post-primary appearance in Virginia -- holding fundraisers June 9 in Richmond and in Fairfax County.

"It doesn't take a lot of courage to go to Martinsville to talk about trade," said Davis, referring to Obama's nuanced opposition to the North American Free-Trade Agreement that some say has erased factory jobs across the rural South.

Obama's Virginia apparatus fired back in a written statement from spokesman Kevin Griffis.

Griffis said Obama will use the Martinsville event and others to press his proposal to provide corporations with tax cuts that "create jobs here, not send them overseas."

The McCain-Obama duel played out as speculation mounts over Obama's selection for vice president and how it might alter dynamics in toss-up states, such as Virginia.

With Kaine said to be on Obama's short list, even Warner and Davis said pairing the governor with Obama could be decisive.

"On balance, picking someone from Virginia will be a net benefit to the ticket," Davis said.

Warner and Davis said the deficiencies of a Kaine candidacy include no experience in military and diplomatic affairs and the ballooning cash shortfall in the state budget, perhaps $1 billion to $1.5 billion.

"It's hard to see how he'd bring strength to the ticket in the national security area," Warner said.

Kaine, an early supporter of Obama, has said in recent days that it is unlikely that he will be the vice-presidential nominee.

But there are hints that Kaine is still in the running. He has been vetted by the Obama campaign.

Contact Jeff E. Schapiro at (804) 649-6814 or jschapiro@timesdispatch.com.

Staff writer Olympia Meola contributed to this report.