Senator Specter jockeys for position

Reaction to Sen. Arlen Specter's defection ranged all the way from the "full support" and "thrilled to have you" from President Obama and the Democratic Party, to "good riddance" from the GOP.

Specter was far from a lock-step Republican, supporting abortion rights and embryonic stem cell research, voting for the stimulus package and opposing a constitutional amendment to ban same-sex marriage, but he did support the invasion of Iraq, backed George W. Bush's Supreme Court nominees and favors school vouchers.

As some observers noted, Specter was to the left of a number of Democrats, including Sen. Ben Nelson.

"Senator Specter is a man of principle and has always worked for the good of the people of Pennsylvania," Nelson said Tuesday. " Just as I support my party when I can and oppose when I must, Senator Specter votes with an independent mind," he said.

It's tempting to call on Nelson to balance the equation, switching to the Republican Party to deny Senate Democrats the 60 votes they need (assuming Al Franken finally wins his Minnesota Senate seat this summer) to prevent a GOP filibuster.

But Nelson knows he is more effective on the right edge of a left-leaning party than he would be left of center in a conservative party, just as Specter knows he might not be able to beat out a conservative candidate in his state's Republican primary.