For all of those who try to make the Abortion compromise business as the president suggested or argue about “hey how can you vote for War and be Catholic” lets play the “Safe legal Rare game”:
You can use that phrase with the word “War”
War should be “Safe”…for civilians.
“Legal” because a country has to right to defend itself or defend its future.
and “Rare” because War should never be the first resort.
Ok now try that with:
Slavery, or Torture, or genocide.
You can’t use that phrase with it because they are intrinsic evils. The same is true of abortion. It just doesn’t work.
This is the argument that should come out every time. This and Nordlinger’s question on why should Abortion be rare if it isn’t wrong?
Update: Added links
Da Techguy's (no longer backup) Blog 
It could be argued that war is an intrinsic evil. Also, abortion should be rare, not because it’s wrong, but because it’s an invasive medical procedure. Invasive medical procedures should all be rare, especially when they can be avoided using preventive measures.
The war argument doesn’t work since that means we should have all submitted to the Nazi’s. There are times when War is just and in fact necessary.
The invasive argument doesn’t work because of things like plastic surgery. I’m not a big fan on non-essential plastic surgery myself I could never see myself spending good money on it, but lots of plastic surgery takes place without a peep.
Catholic teaching is specific on the intrinsic evil on abortion. A person who follows the catholic faith has no choice but avoid corporation with said evil without incurring grave sin requiring confession and absolution.
For the non catholic I would of course argue that science affirms the humanity unborn life and basic ethics dating back to Hippocrates. One of the reasons why life is I think values so cheaply in modern society are those initial steps away from the absolute position favoring life. It allows the judgment of people based on “worth” or “quality of life”.
Of course a society that rejects abortion might still use such methods; for example Islamic dehumanize Jews in their media to justify their murder of them, but as a rule the more you value human life the more just your society will be.