The National Republican Congressional Campaign is going up on TV in Arizona’s 2nd district, making a play for the seat Rep. Ron Barber (D) won in a special election earlier this year.

The NRCC has placed a six-figure buy in the Tucson media market in support of retired Air Force Col. Martha McSally (R), according to several sources who monitor media buys. The broadcast buy is $255,000 and will last from October 5-18.

This news comes hours after the Democratic Congressional Campaign Committee announced it was confident enough in the race to pull a week’s worth of advertising in Tucson and a day after House Majority PAC, a super PAC that supports Democratic House candidates, went into the market.

The House Majority PAC spot was a negative spot that links McSally to Wall Street. The NRCC ad is expected to be a negative portrayal of the incumbent. Barber has already been through the ringer with negative ads from the special election race, so it will be interesting to see how, or whether,  these numbers move over the next couple of weeks.

McSally’s campaign released an internal poll today that suggested the margin between the two candidates is much closer than a Democratic Congressional Campaign Committee poll released earlier this week. The DCCC poll showed Barber ahead by 14 points while the McSally poll showed a dead even race.

Both polls were conducted within days of each other, share similar sample size and have the same margin of error. The biggest divergence between the two polls was McSally’s favorability ratings. In both polls, the candidates were above water in their favorable ratings.

Here’s how the two polls stack up:

• 
  Head to Head Test
  
  
  DCCC Poll: Barber: 54 percent   McSally: 40 percent   Undecided: 6 percent
  McSally Poll:  Barber: 47.3 percent   McSally: 47.3 percent   Undecided: 5.2 percent

• 
  McSally Favorability Rating
  
  
  DCCC Poll: 38 percent favorable/ 32 percent unfavorable
  McSally Poll: 52 percent favorable/ 16 percent unfavorable

• 
  Barber Favorability Rating
  
  
  DCCC Poll: 51 percent favorable/ 32 percent unfavorable
  McSally Poll: 53 percent favorable/ 35 percent unfavorable

The DCCC poll was conducted by Grove Insight from Sept. 27-30 of 400 likely 2012 general election voters via live interviews. It had a margin of error of 4.9 points.

The McSally internal poll was conducted by Wes Anderson of OnMessage Inc. It was conducted Sept. 30-Oct. 1. The live telephone interview survey polled 400 likely general election voters with a margin of error of 4.9 points.

Republicans are cautiously watching this race. They make no pretense that it is as competitive as the contests in Arizona’s 1st and 9th districts, but they stress that McSally is a much stronger candidate than their previous nominee, Jesse Kelly. Kelly lost to Barber in the June special election to replace Barber’s former boss, ex-Rep. Gabrielle Giffords (D). The NRCC spent heavily in that race, only to see Kelly lose by a 7-point margin.

The fact that Republicans are spending here is either an act of confidence or a broader strategic move to draw the Democrats back in.

Still, Barber and national Democratic sources shrug off the McSally poll and the NRCC ad buy. “This doesn’t worry us if that’s how they want to spend their money,” a national Democrat said.

The district slightly improved for Democrats through redistricting. Demographically, it is a pure tossup. But Barber overperformed in his special election. Also, since the January 2011 Safeway shootings that injured Giffords and others, there are special circumstances in this district.

Roll Call rates this race as Likely Democratic.