Do you believe in property rights? That is, within reasonable limits of zoning, you have the right to do with your property as you see fit, as long as it doesn't interfere with the rights of those who own property next to you (such as playing loud music, etc).
Do you believe in the freedom of religion? That people have the right to exercise and practice their chosen religion and affiliate with those that share their beliefs.
Do you believe that people are innocent before proven guilty? That innuendo isn't enough to convict.
If so, you believe the Park51 (aka Ground Zero Mosque) should go forward.
If you believe it shouldn't, you believe that the answer to the first three questions is no.
This whole thing is political theater, designed to whip up a fervor of bigotry and hysteria to garner votes. And it's working.