It seems that the "talks" between Iran and the EU-3 have come to an impasse, and Iran is now saying that it is determined to pursue
uranium enrichment. Clearly this sets it up for a confrontation with the US, and once again the efficacy and worth of the UN will be tested. The US will undoubtedly want the matter referred to the UN Security Council in order to impose sanctions on Iran. Even if China and Russia go along and don't veto such a resolution, what effect would sanctions actually have? Iraq managed to survive under sanctions for 12 years, South Africa even longer. While we could afford to wait with those countries, Iran is only a couple of years away from a nuclear bomb, and according to Israeli intelligence, will achieve a "point of no return" - when they have worked out all technical issues and will be able to proceed without outside help - possibly by the end of this year. Sanctions are, in effect, an acceptance of a nuclear Iran.
Iran is due to have elections in June. There is some hope that some kind of democratic movement will emerge to overthrow the mullahs - although this hope is fairly faint. Despite the continuing reports of demonstrations and riots in a number of cities in Iran - reports that rarely, if ever make the news here - there doe not seem to be enough of an organized movement to remove the mullahs.
More and more, as risky and uncertain as it is, it seems that a military strike on Iran's facilities could be the best option. The best case scenario would be if there were some kind of democratic demonstrations which would then be "supported" by US airpower. Such airstrikes would aim to destroy not just the nuclear installations, but also government command and control assets, military, and Revolutionary Guard installations. This could then have the possibility of overthrowing the mullahs. The worst case scenario is flat out airstrikes on nuclear installations. Since we don't know where all of them are, this would not destroy the Iranian nuclear program, but could delay it for long enough. And once again, the hope would be that the mullahs would be overthrown from within. None of these options are good ones. But once again, the US (not the UN or France) will have to choose and execute the least bad option.