Arizona shows up on all those Electoral College maps as red.

But the color-coding by news networks and major newspapers doesn't tell the full story of a state that is undergoing dramatic demographic changes that portend an election soon when Arizona might be a major battleground — even if it's not this year.

New polling suggests the presidential election is closer here than anyone anticipated.

And political minds on both sides of the partisan divide say that in a future race without an Arizonan on the national ballot, the state could follow the lead of other Western states — like Nevada and Colorado — in being heavily contested.

Population growth, and an influx of both young and Hispanic residents, is shifting the balance of power in the state, pollsters say. From now on, that power is likely to be held by voters calling themselves independent — not Republican or Democrat.

Voters claiming no party account for nearly 28 percent of registered voters in Arizona. Ten years ago, only 14 percent of voters fell in that category.

Some experts, however, say the long-term impact of the current national climate, one that benefits Democrats over Republicans, shouldn't be overstated.

John McCain is still predicted to win here, but with his lead over Barack Obama diminishing greatly in new polling, some say the GOP's hold on the state has officially ended — the party only holds a 4-percentage-point registration edge over Democrats.

"It's not just here, look at the entire intermountain West," said Arizona State University political pollster Bruce Merrill. "New Mexico, Nevada, the whole West has moved significantly from strong red to purple."

A statewide poll taken by Tucson-based Democratic pollsters Carol and Pete Zimmerman two weeks out from the election suggests McCain's lead over Obama falls within the margin of error: 43.5 percent to 41.5 percent, with 10 percent of likely Arizona voters undecided.

Merrill is conducting a similar poll this weekend and predicts that the economic downturn will have narrowed McCain's advantage from the 8-percentage-point lead he enjoyed in a previous poll.

The Zimmerman poll shows Obama's strength coming, as expected, from Pima County, where he has a 19-point lead over McCain. In Maricopa County, McCain holds just a 3-point lead in that poll.

Surprisingly, the poll also found that Obama was leading slightly among surveyed voters over 65 years of age, while McCain led among voters 45 and under. And Obama leads narrowly among independents.

But Carol Zimmerman is careful not to overstate what the poll indicates. She still predicts McCain will win his state. And she says the closeness in the poll results says more about McCain and the 2008 election than it does about long-term political attitudes in Arizona.

"It's a bad year to be a Republican," Zimmerman said. "I think a more popular moderate Republican would win back that Republican support."

Local Republican pollster Margaret Kenski says it all comes down to the candidates. Without a plurality in voter registration for either party, it's hard to permanently swing Arizona to one party or another.

"Obviously the Democrats have picked up, but the real increase has been in the number of independents," Kenski said.

Branding Arizona one color has always ignored the temperament of voters in a state that picked Democratic Gov. Janet Napolitano and Republican Sen. Jon Kyl in the same statewide election cycle, 2006.

Same goes for recent presidential races. Bill Clinton carried the state in 1996, but George W. Bush won in 2000 and 2004.

There are also regional differences. Maricopa County, the state's most populated county, is heavily Republican. But Phoenix proper has a slight Democratic edge.

Pima County is overwhelmingly Democratic due to high numbers in urban Tucson. But the outlying areas of the county lean Republican.

Statewide, Democrats have had registration surges in Maricopa County, which has evened out the GOP advantage statewide.

But at the same time, Republicans are taking the lead in what were once some rural, Democratic counties, like Cochise and soon, Pinal — a potential precursor to changes in leadership there.

As for partisans, they are likely to continue fighting over who controls the state politically — no matter the results of next week's election.

Arizona Democratic Party spokeswoman Emily DeRose said, "It goes without saying that Arizona is turning blue."

"We're already a purple state," DeRose said. "We're not a red state by any means."

DeRose pointed out that before McCain won the Republican presidential nomination, Arizona was often pointed to as a swing state by the national media. But the characterization was dropped after McCain beat out Mitt Romney and Mike Huckabee.

"We will continue to be a Republican state," said Judi White, chair of the Pima County Republican Party. "The gap has narrowed a little bit, but both parties continue to work really hard to register new voters as they come to the state."

A key indicator of the state's political pulse will be known after Election Day. What will be the margin between McCain and Obama? And can Democrats do as they hope: Win at least five of the state's eight congressional seats?

If they do, it would mark the first time the party held a majority of congressional seats in Arizona since 1966.

But Kenski said the tide can easily turn again.

"If the Democrats get in and do what they did that caused them to lose last time we had one of these sea changes, we'll see things swing back," she said. "Everyone's a victim of their own successes."

What to watch for in Arizona

Margin in presidential race: While John McCain is generally assumed to have his home state in the bag, the margin by which he wins Arizona could say a lot about the political atmosphere here. And if he loses the presidency, how he does here could influence what kind of race unfolds in 2010, when his term in the U.S. Senate ends.

Control of state House: Democrats are aiming to win control of the state House of Representatives. In order to do so, they need to retain their seats and win four more, many in Republican-leaning areas.

Congressional races: The outcome of congressional races — 8th District in Southern Arizona and 1st, 3rd and 5th districts elsewhere in the state — will determine how Arizona is viewed nationally. Right now, the delegation is split, with four seats held by Republicans and four by Democrats.

● Contact reporter Daniel Scarpinato at 307-4339 or dscarpinato@azstarnet.com