National Democrats are coming to the defense of Rep. Raul Grijalva (D-Ariz.).

Grijalva has recently been putting up some weak poll numbers in a heavily Democratic district and is under fire from conservative groups over his call for a boycott of Arizona.

To help save the party from an embarrassing defeat, the Democratic Congressional Campaign Committee went up on the air with a TV ad targeting Grijalva's opponent, Republican Ruth McClung.

The ad hits McClung for supporting a "new national sales tax" and "tax breaks for corporation shipping jobs overseas."

It started airing Saturday. The DCCC had previously only had reserved TV airtime in the district starting Oct. 26, according to a Republican strategist who tracks Democratic ad buys.

Earlier this week, Americans for Tax Reform (ATR), headed by Grover Norquist, launched a TV ad hitting Grijalva for calling for a boycott of the state.

Grijalva called for an economic boycott of Arizona after the state legislature passed its controversial law against illegal immigration. He's since backed away from those statements.

Still, two recent polls show Grijalva — who hasn't faced a tough challenge in his eight years in the House — within the margin of error against McClung, a 28-year-old rocket scientist employed by a defense contractor.

Sensing an opportunity, national Republicans including Sen. John McCainJohn Sidney McCainTrump considering pardon for boxing legend after call from Sylvester Stallone GOP poised to advance rules change to speed up Trump nominees The Hill's Morning Report: Inside the Comey memos MORE (Ariz.), former Massachusetts Gov. Mitt Romney and former Alaska Gov. Sarah Palin have endorsed McClung. Her campaign fundraising has taken off as a result. McClung recently raised $100,000 online in a single day, the Tucson Citizen reported on Friday.