This is shaping up as quite a presidential election: a close campaign taking on the trappings of what generals call “total war.”

If you find the phrase discomfiting, recall that the word “campaign” comes from the military world, and remember that U.S. Grant fought the Wilderness Campaign of 1864 four years before he engaged in his first presidential campaign. (He won both.)

This is, to keep the martial metaphor, a war with several fronts. Some are obvious: issues such as abortion, national security, energy policy, taxes, maybe even inflation. Some are less visible, with more subtle implications. Here are some of the skirmishes that might make the difference in November:

¢ The candidates’ efforts to invade their rival’s base.

With forays into red states such as Virginia, North Carolina, Missouri and Montana, Barack Obama is courting voters in states that went for George W. Bush in both 2000 and 2004. The prominence of black voters in the first three states explains the Obama potential. Montana was one of a number of reliably Republican states that Obama carried in his struggle with Hillary Rodham Clinton; the influx of new voters there and the fresh appeal of the apparent Democratic nominee make it actually possible that the Democrats could corral that state.

But Obama won’t be the only one fighting in unfamiliar territory. Sen. John McCain will find opportunities in Democratic-leaning states where Clinton prevailed in her fight against Obama. Principal target: Pennsylvania. Second target: Michigan, though Obama’s name didn’t appear on the ballot there.

¢ It depends on what the meaning of “change” is.

Everyone wants change in 2008, because the status quo – gasoline at $4 a gallon, the financial markets in turmoil, two wars in Asia, the whole country in a funk – is not exactly a bowl of cherries, and that is without mentioning the ever-higher cost for cherries and just about everything else.

Obama will fairly scream “change” the moment the Democrats present him with their nomination in Denver in late summer. He looks different, he talks about a world and a Washington that are different, and he ran for president in a fashion that was altogether different (with big money from small donors and a big push in caucus states, many of them small).

But then, McCain is different, too. He looks at the world in a way that is different, and he looks at Washington in a way that is way different, at least from regular Republicans. He is change in a shock of white hair.

So the question is not whether America wants change in 2008, but how much change America can abide. Neither man is a safe choice from the point of view of big business, lobbyists and entrenched interests in Washington. Obama may represent too much change. But before you conclude that that provides McCain with an advantage, consider that he might not represent enough change.

¢ The difficulties of a faith-based initiative.

For a generation, American politics has inched toward the pulpit, and the country has elected three exceedingly devout presidents (Jimmy Carter, Bill Clinton and George W. Bush) since Watergate, when Americans’ loss of faith in their institutions reached a symbolic crossroads.

But it’s hard to imagine a candidate less suited to play the faith card than one who recently repudiated his minister and church, unless of course it is a candidate who in past years luxuriated in being repudiated by the religious conservatives who were an important part of his party’s electoral coalition.

Instead, Americans must choose this November between two men who project a faith of a different sort: one who has staked his political career on faith in the redemptive power of hope, and another who has staked his identity on faith in America and its mission, sometimes military, sometimes moral. These men personify piety outside the pew, which is an appealing feature, but which leaves millions of people of faith in both parties struggling to sort out their choice for Election Day.

Some quick examples of how the calculus is in flux this time: Evangelicals are skeptical of McCain. Jews are skeptical of Obama. Meanwhile, Catholics remain the great prize in American politics. In every election since 1972, the party that has won the Catholic vote has won the election.

¢ The fight to define what the election is about.

The 2004 election was about moral issues. Voter interviews put moral values at the top of the issues that Americans cared about four years ago, and, among those who cited moral issues, four out five sided with President Bush. The economy was a close second, and four out of five of the voters who selected economic issues sided with Sen. John F. Kerry of Massachusetts, the Democratic nominee.

This year everybody thinks the economy is in the tank, and while both candidates will seek the moral high ground – that is what presidential candidates do – neither will be able to claim the moral-values vote.

From this vantage point in June, so much depends on so much that is unknown – in the economy, in Iraq, in the war on terror, at the gas pump, at the supermarket checkout counter, in November.

The keys could be in America’s oldest voting group (white males) and in America’s newest voting group (the digital youth). McCain will have an advantage in the former. Obama, using his own appeal to build on the inroads John Kerry made among 18-to-30-year-olds in 2004, will have an advantage in the latter.

The prognosis is for a very close struggle. Stuart Rothenberg, an unusually perceptive political analyst, last week even raised the specter of one candidate winning the Electoral College while the other wins the popular vote. We did that recently. It was not ideal.