It appears the Pennsylvania Democratic electorate is rapidly moving toward Rep. Joe Sestak in his May 18 primary challenge to former long-term Republican senator Arlen Specter. Specter left the GOP last year when he thought he would lose the Republican primary and determined that running as a Democrat would give him a better shot at keeping his seat. With the backing of the White House, Specter has led Sestak in the polls for months, but with the election less than a week away, the trend is now moving in Sestak’s direction.

A new Quinnipiac poll has Specter with a narrow two-point lead and a surprisingly large number of undecided voters this close to the election.

U.S. Rep. Joe Sestak continues his stretch run in the Pennsylvania U.S. Senate primary and now trails incumbent Sen. Arlen Specter by a too-close-to-call 44 – 42 percent among likely Democratic primary voters, according to a Quinnipiac University poll released today. Another 14 percent of Democrats are undecided, and 29 percent of those who name a candidate say they might change their mind.

This result approaches those from Franklin & Marshall (Sestak 38 – Specter 36), Muhlenberg (Sestak 45 – Specter 45), and Rasmussen (Sestak 47 – Specter 42). They all show a very close race, now with a slight edge for Sestak, and a trend clearly favoring the challenger.

If Specter does end up winning the Democratic primary, it will be a sign of the party control President Obama has centralized at the White House. The Democrats in Pennsylvania have been voting against the Republican Senator Arlen Specter for decades. Specter did not switch parties because of some ideological conversion moment, but simply to get re-elected. If Democratic grassroots back him now just because the establishment says so, it will be an impressive display of the top-down nature of the current Democratic Party.