By Cameron Joseph - 04/06/12 04:49 PM EDT
Tester's campaign did not say how much is behind the ad, but his first ad had about $50,000 behind it, according to sources.
None of Tester's ads have mentioned his party affiliation and instead have focused on bipartisan work and his independent streak — a smart move in the Republican-leaning state. Rep. Denny Rehberg, his GOP opponent, has not gone up on the air yet.
The Hill rates this race a toss-up.