What approach should the United States take with Iran in regards to their continued development of nuclear capability?
(sanctions, covert action, assist Israel in strikes, conduct own overt strikes, etc.)?
Of course, no one knows for certain what the best approach should be.
Ideally, the best action would be to persuade Iran to allow inspectors who could verify that they were not creating weapons. However, this does not seem to be working in any real way. This is particularly true because the majority of Iranians seem to support the nuclear program.
Failing that, the best thing to do would be covert actions. Someone used the computer virus to damage Iranian centrifuges. Someone has been killing Iranian scientists. These are effective ways to delay the program but are probably not long-term solutions since it would be extremely difficult for any covert action to completely destroy Iran's nuclear capabilities.
That only leaves strikes, either by ourselves or by Israel. This, too, is a bad choice. Strikes are unlikely to destroy all of Iran's capabilities and would have far-reaching consequences.
There are simply no good options here.