Look, I agree, if you HAD to take on one issue at a time then yes, I would deal with the Persians trying to nuke us. But, you know that realistically we don't have to deal with just one thing at a time.
Look at it this way, what good would it do to have all the foreign bad guys under control and have an efficient and effective military only to collapse from within, a la Rome.
We have to address both (or all) the issues threatening this society.
Actually high taxes, regulation, government corruption destroyed Rome from within; that is why I think they should take top priority over homosexuality.