John Kerry issued the following statement in response to Bush's veto:
“This wasn’t a pro-life veto. This was a political veto, and I believe Americans will veto this President’s narrow political agenda in November.
“Honoring the sanctity of human life means giving hope to the 100 million Americans suffering today from illnesses that stem-cell research may one day help cure, not vetoing hope. Instead, because of politics, more than 3,000 Americans will continue to die every day from diseases that might one day be treatable because of stem-cell therapy. We can support our scientists, help the sick, and ensure that our legal and ethical boundaries continue to reflect our unshakable sense of human dignity and the value of human life. Today President Bush failed that test. This was not a simple decision, but it shouldn’t have been a close call, let alone the wrong call.
“Instead of vetoing runaway spending or cuts in medical services for the poorest Americans, the president has chosen to veto the promise of groundbreaking research. On this issue President Bush has said one thing and done another. That’s not leadership, it’s playing politics with people’s lives, and it’s unacceptable.”
ThinkProgress has video of Bush's "spare parts" statement here.