A new Research 2000 poll reaffirms what a separate Rasumussen poll found earlier this week: that in the last month Rep. Joe Sestak (D-PA) has made serious gains on his Pennsylvania Senate primary opponent, Sen. Arlen Specter (D-PA).

Specter now leads Sestak 48-33 among likely voters. But that 15 point margin is down by 30 from May when Specter lead 56-11. And 40 percent of voters still don't know who Specter is.

Meanwhile, according to R2K, both men still lead Pat Toomey--Specter 45-40, and Sestak 42 41. Both men have lost ground in recent weeks, though. Specter was throttling Toomey 55-31, and Sestak enjoyed a more comfortable 37-32 margin three months ago.

Though Toomey's clearly gaining ground, Rasmussen recently found that Toomey had actually surpassed both of his potential rivals.