Of course, the main issue raised by a Tom Tancredo presidential bid is not abortion but immigration. Many immigration hawks are pleased to hear that Tancredo may be running; it gives them a chance to send a message about the borders during the Republican primaries.
These voters should be a bit less pleased. The fact that Tancredo has taken a step toward a run suggests that no Republican who can actually win the nomination has decided to run on anything approximating their preferred platform.