On “Meet the Press” this morning, Senator Arlen Specter said a big factor in his decision to become a Democrat was that the Republican Party had moved “far to the right.”

Specter told David Gregory on NBC’s “Meet the Press” that he had determined “with polls and a lot of personal contact” that his reelection prospects as a Republican were “bleak.”

But he added: “There’s more than being reelected here. There’s the factor of principle. The Republican Party has gone far to the right since I joined it under Reagan’s big tent. ... In recent times, I have diverged materially from the Republican line ... As the picture has evolved, I felt a lot more comfortable – as a matter of principle – with Democrats than Republicans.” ...

Asked his core principles, the first two Specter listed were “freedom, a woman’s right to choose.”

Specter, a survivor of the cancer Hodgkin’s lymphoma, has opened a website to push for more medical research.

“If we had pursued the war on cancer, which President Nixon declared in 1970, Jack Kemp might be alive today,” Specter said. “This medical research has prolonged or saved many lives, including mine.”