From Kevin Drum's Comment box at the Washington Monthly:

Aborted fetal tissue is used by Merck in MMR vaccines. I did not know that.

[A] close reading of the literature published by Merck, the
primary producer of the Measles-Mumps-Rubella (MMR) vaccine, indicates that they use aborted human fetal tissue in the production of this vaccine. Not only that, but several other vaccines use it as well.

The USCCB has a statement on this:

To defend his recent decision on stem cell research, President Bush has compared it to the moral judgment that it may be acceptable to use a vaccine cultured in fetal tissue that ultimately came from induced abortions. The President's
analogy is invalid because it blurs together two very different questions arising from the use of fetal tissue in medical research:

Interesting. The Bush pro-life creds is slowly getting eroded each day it seems. Stats have been floating around showing that abortions have increased under Bush reversing the downwards trends of the Clinton/Gore years. Close examinations of Bush's prolife standing reveal more pandering and a true desire for fighting or protecting life. He did learn one thing from Deal Hudson, that Catholics are suckers for the phrase "Culture of Life."

Now this use of fetal tissue in MMR and other vacines and President Bush's chest-swelling-pride that he is the first president to support ESCR, further undermines and exposes Bush's commitment to the conservative anti-abortion principles.

Kerry Catholic supporters feel that one must show a commitment to life in one's fights, even if the approach differs. While the we may argue that the anti-abortion conservative push is misguided, I think we all respect the intent and commitment to the principle of life. We Kerry supporters fight for life by focusing on the social and demand side of solving the abortion issue. We fight for life also in the visible tangible lives we see, knowing that it rings false to claim love for life not seen, yet ignore the visible tangible manifestations of life we experience daily. Life is life, unborn and post-born.

As for the President, it is not clear where he stands. (Also see the following beliefnet article on the candidates and abortion.)

--He refuses to guarantee a litmus test for appointing SCOTUS judges.
--He has been silent about a constitutional ban on abortions
--He claims life begins at conception but then is proud to be the first president to sponsor ESCR.
--He supports the use of aborted fetal tissue in vaccines, which should be contrary to the conservative anti-abortion principles.
--Abortions have increased under his watch and should he have a second term, there is no reason to believe that the trend will be reversed. (Jcecil3 has a great post on what it would actually take to reverse Roe v Wade.)

The point is, what is Bush's pro-life principle? For Kerry and Kerry Catholics, it is a consistent demand-side approach, on the whole; while the conservative anti-abortion crowd has a consistent legislative prohibitive "supply-side" approach. Bush and the RNC, on the other hand, have shown no desire actually reduce abortions, rather they see this more as a political issue to build their base with.

The beliefnet article mentioned above says:

Is Bush really a right-wing pro-life hardliner who’s kept his real views quiet so he can be re-elected and then ban abortion and appoint a gaggle of Scalias to the court? Or is he a political pragmatist who has no intention of banning abortion but just wants religious conservatives think he will?

Also, via Welborn, this Denver Post article captures the sentiments of many in the conservative anti-abortion movement, that the Republicans have been playing them like a drum. Besides recounting the obvious fact that it has been Republican courts that established and upheld Roe v Wade, he adds to the list of what Bush has not done (or even proposed), if he really is interested in protecting life according to the conservative anti-abortion principles.

Bush's government has not stopped the use of the morning-after abortion pill, or privately funded stem-cell research using human embryos, or the slow, frozen, extinction of fertilized eggs in U.S. fertility clinics.

Many Catholics are begining the appreciate what "Culture of Life" really means. And one thing they are sure of is that "Culture of Life" is not synonymous with "Republican Party."