ABC News' Teddy Davis Reports: In his most explicit comments to date, Pennsylvania Sen. Arlen Specter (D) has issued a statement saying he opposes sending 30,000 additional American troops to Afghanistan. Specter, who is up for re-election next year, is facing stiff competition in both the Democratic primary from Rep. Joe Sestak, D-Pa., and in the potential general election from former Rep. Pat Toomey, R-Pa. Specter made national headlines earlier this year when he switched from the Republican to the Democratic Party. Back in September, Specter delivered a Senate floor speech expressing doubt about the mission in Afghanistan but his Tuesday night reaction to President Obama's West Point speech is the first time that he has joined Sen. Russ Feingold, D-Wis., Sen. Bernie Sanders, I-Vt., and Sen. Barbara Boxer, D-Calif., in stating explicit opposition to the troop buid-up without any caveats. Specter strongly hinted that he was going to oppose the troop build-up during a blogger conference call which was held on Nov. 19. Tuesday's statement was even more definitive, however, because Specter was previously holding out the possibility that the Obama administration might prove that the additional U.S. troops were indispensable to the fight against Al Qaeda. Here is the full Specter statement on Afghanistan: “I oppose sending 30,000 additional American troops to Afghanistan because I am not persuaded that it is indispensable in our fight against Al Qaeda. If it was, I would support an increase because we have to do whatever it takes to defeat Al Qaeda since they’re out to annihilate us. But if Al Qaeda can operate out of Yemen or Somalia, why fight in Afghanistan where no one has succeeded? “I disagree with the President’s two key assumptions: that we can transfer responsibility to Afghanistan after 18 months and that our NATO allies will make a significant contribution. It is unrealistic to expect the United States to be out in 18 months so there is really no exit strategy. This venture is not worth so many American lives or the billions it will add to our deficit." ABC News' David Chalian and Z. Byron Wolf contributed to this report.