Is Iran part of the non-proliferation treaty? If so, then no- we have every right to stop them however possible. I'm just saying that we can't possibly police the whole world- if there are rogue nations out there that have not signed on, then we have no choice but to watch them closely and then sic Mossad on them.
We are Israel's allies, and we should defend them. Iran has stated that they want to erase Israel fromthe map, so it's a fair assumption that if they have the means, they will probably try. I'm not clear as to whether they signed any non-prolif treaties in the past- if so, then we need to stop them, and we have the right. None of this handing them technology in the hopes that they will cease their pursuits, because let's face it- they aren't looking for cheap energy alternatives.
However....We simply cannot just barge into another country because they are engaging in behavior that makes us nervous, at least if they are not breaking any treaties, etc. We can make things uncomfortable for them, but this pre-emptive strike business is dangerous and contrary to who and what we, as a nation, are supposed to represent. Tread on us or our friends and your ass is grass. But we are in danger of becoming the neighborhood bully, beating up anyone who we see is a threat, and one day those other kids are gonna grow up and come back at us.