In the end, the power that the Democrats would gain by giving themselves the ability to ration health care was more important to Congressman Stupak than was the pro-life stance that he had claimed to hold.
You can hear Stupak try to explain as Megyn Kelly rips him a new one.
He had 4 votes. Enough to kill the bill.
Stupak sold out. (and cheaply at that.)
See also: Schlafly: Health Care Vote Set to Expose the Myth of the 'Pro-Life Democrat'
"Any formerly pro-life Democrat who casts a 'Yes' vote for this Senate health care bill tonight will be forever remembered as being among the deciding votes which facilitated the largest expansion of abortion services since Roe v. Wade."
"Mr. Stupak and his Democrat followers have now clarified that you cannot be pro-life and be a Democrat. If abortion was truly their biggest issue, they wouldn't willfully align themselves with the Party of Death."
I think that Phylis Schafly makes a strong argument. When tested, Stupak valued life less then he valued the Democrat Party's accrual of political power.