While a candidates stance on one issue is not enough to qualify them for a particular position, a candidates stance on an issue is enough to disqualify them from a particular position.
Barack Obama is unashamedly pro-death. Based on this information, I am unable to vote for him in good conscience. Regardless of his stance on other issues; his position on the abortion issue is enough to disqualify from the list of candidates I can vote for.
While John McCain may not have the best stances on other issues, he does not support the destruction of the most defenseless group of American citizens as does Obama. Therefore, as a Christian I must vote for the candidate who supports the protection of innocent human beings.
There are six things that the LORD hates,
seven that are an abomination to him:
haughty eyes, a lying tongue,
and hands that shed innocent blood,
a heart that devises wicked plans,
feet that make haste to run to evil,
a false witness who breathes out lies,
and one who sows discord among brothers.
– Proverbs 6:16-19 (ESV, emphasis mine)