Senior Regional Correspondent

Considering that next year’s U.S. Senate contest in Virginia is shaping up to be the most watched, most costly, most consequential race in the nation, it’s remarkable that both of the two likely candidates surely view the campaign with some measure of personal resentment.

Former governor and current Democratic National Committee Chairman Tim Kaine has made no secret of his lack of appetite for the job. He’d prefer another executive position — a Cabinet post, say.

But he’s expected to confirm in early April that he’s entering the Senate race. It’s all party loyalty. He’s the strongest available candidate to try to hold onto the seat being vacated by a fellow Democrat, Sen. Jim Webb.

The probable Republican nominee, former governor and senator George Allen, must begrudge the race because he never anticipated having to run it. He narrowly lost the Senate seat to Webb in 2006, partly because Allen was so busy thinking of eventually running for president that he became overconfident.

Now, instead of planning for higher office (or even holding it already), Allen is trying to reestablish his political career. After formally entering the Senate contest in January, he has the added burden of having to overcome a tea party challenger in the GOP primary just to get the nomination.

Virginians and their neighbors are going to see a monumental political battle, including heavy television ad campaigns, for unusually high stakes in a presidential year. The November 2012 voting results in the Old Dominion, a critical swing state, could determine control of the Senate or the presidency. Or both.

“It’d be a good time to own a TV station in Virginia. It’s hard to imagine that there will be more money spent per capita in any other state, except maybe New Mexico, which has a similar dynamic and fewer people,” said Ed Gillespie, chairman of the national Republican State Leadership Committee and a former chair of the Virginia Republican Party.

With the election 19 months away, it’s far too early to make a reliable prediction about who’s going to win. That will depend a lot on developments yet to come in the economy and possibly foreign affairs, and on how President Obama is perceived compared with whoever ends up being his Republican challenger.

But when both of the expected Senate candidates have such extensive records in public life, it’s not too soon to ask them to explain some of the sour events in their pasts. I’ve got one apiece that I’d like Allen and Kaine to address. They might as well do it now, because I know their opponents will surely be raising the same issues.

For Allen, I don’t think he’s adequately responded to concerns that his notorious “macaca” comment in the 2006 campaign bespoke a broader, personal discomfort with racial and ethnic diversity in Virginia.

In a videotaped moment that contributed to his loss, Allen mocked a young, Indian American volunteer from Webb’s campaign and called him “macaca,” a derogatory term for “monkey” in some countries.

Allen apologized and said he learned from what he called a mistake. He wrote in a 2010 book that he thought “macaca” was a nonsense word.

Even if we accept Allen’s defense that he didn’t know the word was a racial slur, I think an equally big worry is the context in which he used it. At the event in rural Virginia near the Kentucky border, Allen said to the volunteer, sarcastically, “Welcome to America and the real world of Virginia.” It’s hard to interpret that in any way other than Allen thought a person with brown skin was out of place in the “real” Virginia.

From Kaine, I think Virginians deserve to hear a fuller explanation of what went awry in the last year of his governorship, which was marred by at least three apparent missteps.

First, he closed 19 state highway rest stops, citing lack of funds. That might seem trivial to outsiders, but it infuriated residents. ­­Since then, Kaine’s Republican successor, Gov. Bob Mc­Don­nell, said an audit of the Virginia Department of Transportation found large amounts of unspent dollars that could have been used to keep the rest stops open all along.

Second, as his term ended in early 2010, Kaine left Mc­Don­nell a budget proposing a sizable income tax increase even though the economy was still slow and the Democrat knew the plan had no chance of being enacted. Sure enough, it went nowhere.

Finally, all this occurred at a time when Kaine had taken on the additional job of Democratic Party chairman. He swore it didn’t interfere with his work in Richmond, but how could it not? Virginians elect a governor for only one term and have a right to expect him or her to do the job full-time for all four years.

As the two heavyweights enter the ring, they should start their campaigns by clearing the air with voters about concerns lingering from the past.