Yesterday I pointed to Rasmussen Reports polling showing John McCain leading Barack Obama by a mere 5 points -- 51 percent to 46 percent -- in Arizona. This survey came on the heels of two more recent Democratic polls showing McCain under 50 percent and leading by just 2 and 4 points. Now comes word that GOP polling shows largely the same result, and a forthcoming nonpartisan survey might not be too far off, either.

More disturbingly for Republicans, at least one internal Republican poll conducted toward the end of the week showed McCain clinging to a tiny 3-point lead. McCain is tied in Maricopa County, usually seen as a death knell for any statewide Republican candidate, but he makes up the difference with a strong performance in the northern part of the state.

Bruce Merrill, a political scientist who conducts the nonpartisan Cronkite/Eight poll for Arizona State University, told the Arizona Daily Star he expects his next poll to show a narrower advantage for McCain than his last survey. That survey, conducted during the final week of September, showed McCain leading by seven points, already a slim margin for a candidate's home state. Merrill's poll was being conducted over the weekend.

The last few days I have posited that it likely would not be worth it for the Obama campaign to go into Arizona this late in the process. But the more data I have seen quite unanimously showing the race in Arizona to be in the low single-digits, it might actually be worth it -- if the resources permitted it -- to spend a few hundred thousand dollars in late advertising in the state. Again, resources permitting, the upside is fairly high -- 10 electoral votes -- while the downside (a few hundred thousand dollars) isn't nearly as high. Yes, Obama's national advertising, including the 30-minute spot that will run on the major networks (including Univision), will saturate the state. But a targeted television buy in the state could just put Arizona genuinely in play one week from election day.