When Sen. Arlen Specter (Pa.) decided to switch parties and become a Democrat, it was widely assumed he would retain some, if not all, of his seniority.

As details were released that Specter's switch had been discussed with Senate Majority Leader Harry Reid (D-Nev.) for years, it was widely assumed that some gentleman's agreement was made so that Specter would be a senior member of his new conference and on his committees. Surely, after so long in the Senate, Specter had mastered the art of negotiation. He couldn't be the world's worst high-stakes poker player, could he?

Well ...

As reported last night by Paul Kane of The Washington Post, the words "Specter" and "seniority" will be mutually exclusive for the rest of this Congress.

The Senate last night voted to place Specter in junior slots in each of the committees. That it did so by a unanimous voice vote means that Specter, who told the press he would retain his seniority, raised no objection to his own political emasculation.

In practical terms, this means Specter, after 28 years in the Senate, will not even be a Senate Appropriations subcommittee chairman this Congress, and that when the Senate Judiciary Committee begins hearings on whomever President Obama nominates to the Supreme Court, the last questioner — the bottom man on the totem pole — will be Arlen Specter.

In another committee, the Special Committee on Aging, Specter is now outranked by his own state's junior senator, Bob Casey Jr. (D). That Specter is now outranked by someone who has been in the Senate only two years — and was 20 when Specter was elected in 1980 — speaks to the disregard in which Democrats hold Specter.

The days since the switch have not been kind to Specter. His claim that he would retain his seniority was false. He's sparred with prominent members of the media who reported Specter said he would be a loyal Democrat (those who reported this stand by their respective stories). He's also proven, as he faces a potential Democratic primary somewhat similar to the one that caused him to bolt the GOP, that he won't be a loyal Democrat, telling The New York Times, "There's still time for the Minnesota courts to do justice and declare Norm Coleman the winner."

All of this has a cumulative effect that threatens Specter's reelection. As the Post's Kane puts it, "Without any assurance of seniority, Specter loses a major weapon in his campaign to win reelection in 2010: the ability to claim that his nearly 30 years of Senate service places him in key positions to benefit his constituents."

Meanwhile, Sen. John Cornyn (Texas) and his team at the National Republican Senatorial Committee (NRSC) have kept the pressure on Specter — reminding Washington and Pennsylvania media of Specter's support of Justices Roberts and Alito and robo-calling, so far, more than 100,000 Pennsylvania Democratic primary voters reminding them of President George W. Bush's enthusiastic support of Specter in 2004.

With Specter effectively a freshman again, don't expect these criticisms to let up anytime soon.