A super-PAC backing Senate candidate Dan SullivanDaniel Scott SullivanBiden's oil stance jars Democrats in tough races Coordinated federal leadership is needed for recovery of US travel and tourism The Hill's Campaign Report: Democrats break fundraising records in Senate races MORE (R) is on the air with an ad hitting Sullivan's primary foes, a sign he may not have as comfortable a primary lead as many outside Alaska have believed.


The ad, from Alaska's Energy, America's Values, takes to task both 2010 Senate nominee Joe Miller, who a woman says "troubles" her. She also says she's "really disappointed" in Alaska Lt. Gov. Mead Treadwell (R) for his attacks on Sullivan, describing Sullivan as the "only candidate" who can beat Sen. Mark Begich (D-Alaska).

Sullivan has surged to a big lead in the money race and has led in a handful of nonpartisan primary polls, leading many in Washington to assume the primary is his to lose. But some Alaska Republicans have privately said Sullivan's lead might not be as sturdy as it appears from afar, and the fact that a group backing him feels the need to spend money hitting his primary opponents indicates the race might be tightening.

Sullivan and Begich have been engaged in a robust air war against each other. But Begich has also re-engaged with Treadwell in recent weeks, attacking him in press releases after having mostly ignored him for months.

The race is a pivotal battle for Senate control, and Democrats have felt good about Begich's chances in the heavily Republican state. A protracted, hard-fought primary heading into August could hurt GOP chances at a pickup in the state.