Stem Cell Restrictions Un-American?

Chris Nolan argues that by not being sufficiently supportive of embyonic stem cell research, President Bush is "Un-American". I have objections to some of what she's written which leave her argument unconvincing to me. Before she can make her main argument, she dismisses the ethical concerns of opponents thusly:

Now, I have a great deal of respect for people who argue that destroying the day- or hours-old embryos is, in essence, the destruction of human life. But I also believe they are wrong.

What is her opposing argument?

Life begins gradually; it's a subtle process that none of us should take for granted, one to which we should give careful thought. That's why we have ethics.

Well, life is a subtle process, to be sure, but it does have a beginning and an end. Ms. Nolan's statement on when human life begins leaves a question. What is the point once crossed we can proclaim a life exists? Based on her ideas it's pretty easy for people to arbitrarily pick a time based soley on the researcher's convenience. The people who favor this kind of research (and abortion, for that matter) all seem to be a little vague on this point. If we can't define this basic starting point, isn't it ethically and morally safer to assume conception as the starting point? Even if it is inconvenient?

Ms. Nolan then likens the death involved in cloning research to those of the astronauts in the space program. Her comparison misses the mark simply becuase the people involved in the space program never conducted a mission where the plan included the death of the astronauts sent on the mission. This is unlike embryonic stem cell research, where the intent is to destroy human embryos to extract stem cells. Is there some reason the intent doesn't matter?
(via Instapundit)
Update: I neglected to add the appropriate links to Ms. Nolan's post. The oversight has been corrected.