Arizona Gov. Janet Napolitano (D) on Tuesday declined to rule out either leaving her job early to join the next White House administration or running for Senate in 2010, when she will be termed out of office.

“I don’t answer those questions,” Napolitano said, when asked if she would accept an offer from presumptive Democratic presidential nominee Sen. Barack Obama (Ill.) to join his administration, should he win the White House this fall.

When asked if she plans on running for Senate in 2010, Napolitano was equally noncommittal.

“I don’t answer those questions, either,” the governor said in advance of her scheduled address to Democratic National Convention delegates Tuesday evening.

Napolitano was interviewed briefly after addressing a breakfast gathering of Arizona convention delegates. The delegates themselves are optimistic that they can cause trouble for Sen. John McCain (Ariz.) this fall on his home turf — if not outright cost the GOP presidential nominee the Grand Canyon State’s 10 electoral votes.

If McCain were to lose the presidential election to Obama and remain in the Senate, the Arizonan would be 74 in November 2010 when it would be time for re-election. That could prompt speculation that after two failed White House bids and more than 25 years in Congress, he might choose to retire.

If McCain is elected president, it would fall to Napolitano to pick his successor — but under state law, she must select a Republican. That person would serve until McCain’s term ended in 2010.

Wealthy developer Jim Pederson, who made his first run for office in 2006 but lost to Sen. Jon Kyl (R), said he would make a decision on whether to run for Senate by the end of this year. But Arizona Attorney General Terry Goddard (D), echoing the general consensus among Democratic insiders in his state, said his party’s 2010 Senate nomination is Napolitano’s for the taking, if she wants it.

Napolitano, a former state attorney general now serving her second term as governor, remains popular in Arizona.

According to an Aug. 13-15 Mason-Dixon poll, 66 percent of Grand Canyon State voters gave Napolitano positive marks, with 29 percent saying she is doing an excellent job as governor and 37 percent saying she is doing a good job. The survey’s error margin was 5 points.

Not only is Napolitano seen as a leading candidate for Senate in 2010, she may be the favorite. But Arizona Republicans offer a different view, contending that they would field a formidable candidate in 2010 if McCain’s seat opened and noting that Pederson failed to defeat Kyl in 2006, the best Democratic year in a generation.

“It is hardly a secret that Gov. Napolitano has aspirations for higher office. Her claims otherwise are about as valid as her discussions about controlling spending,” said Camilla Strongin, spokeswoman for the Arizona GOP. “Let’s hope before Potomac fever sets in she cleans up our multibillion-dollar budget deficit.”

Meanwhile, Democratic delegates attending this week’s presidential nominating convention sound practically giddy at the opportunity to deny McCain a home-state win as he battles with Obama in what is currently a close race.

The Mason-Dixon poll showed McCain with a 47 percent to 41 percent lead over Obama, with 12 percent undecided, giving the delegates in Denver hope that their candidate can win the state. Democratic activists are vowing to work hard on the ground this fall to help Obama do to McCain exactly what then-Texas Gov. George W. Bush did to Vice President Al Gore in 2000, when Bush beat Gore in his home state of Tennessee.

“We’ve got a great opportunity to take Arizona for Barack Obama,” said Arizona delegate John Adams, a retired Army brigadier general and Tucson resident. “A hometown guy might have an advantage. John McCain hasn’t shown himself to be interested in Arizona.”

Kit Filbey, a delegate from Mesa, in the heart of Rep. Jeff Flake’s (R) solidly Republican district — she moved there from Denver four years ago — believes that her new home state is winnable for Obama this year.

However, Filbey suggested that if McCain picks ex-Massachusetts Gov. Mitt Romney (R) as his running mate, it could motivate Arizona’s large Mormon community and put Arizona out of reach for the Democratic White House ticket. Romney is a devout Mormon.

Filbey, who according to party officials is one of the Arizona Democratic Party’s most reliable grass-roots volunteers, said she relishes the opportunity to aid the Obama-Biden campaign in the 6th district.

While conventional wisdom suggests that McCain’s position at the top of the ticket would make Arizona less competitive this fall, Filbey said grass-roots Democrats are more motivated than they otherwise might have been, as a victory would be that much sweeter. Filbey also said that many of her neighbors are newer Arizona residents, just as she is, and therefore are not connected to McCain the way longer-term Arizonans might be.

“I think we really have a chance,” Filbey said.

Strongin dismissed out of hand any suggestion that the Grand Canyon State would be competitive this fall, let alone swing for Obama.

“McCain will win Arizona. Anyone thinking otherwise is suffering from something other than the thin Denver air,” Strongin said. “Sen. McCain is extremely popular in Arizona because Arizonans know McCain’s track record of tackling tough issues. As they say: Actions speak louder than words.”