Arlen Specter's 30-year run in the Senate -- and his reputation as a political survivor -- is facing real trouble with just one week to go before the Pa primary.

Joe Sestak is pulling further ahead of Specter in two new polls. The Muhlenberg daily tracker, which first noted he was ahead among likely Dem voters, continued to show Sestak with a lead and now Rasmussen does too. Here's the latter:

The latest Rasmussen Reports telephone survey of likely Democratic Primary voters in the state shows Sestak earning 47% of the vote while Specter picks up 42%. This marks the first time Sestak has held the advantage in the race.

Specter’s support has slipped from 48% in March to 44% a month ago to 42% today.

The numbers for Sestak have been going in the opposite direction from 37% in March to 42% a month ago to 47% today.

Sestak is up by the same 5 digits in today's Muhlenberg/Morning Call poll.