For MEB, always.
One thing that is very clear in the "coercive diplomacy" literature is that if one is trying to coerce a State into doing something it definitely wouldn't do, absent the coercion, economic sanctions being the most popular instrument of coercion, deadlines are an important tool, as that is put up or shut up time all around.
A deadline is put up or shut up deal, for both sides.
For the coercing party, putting a deadline out there puts all your credibility on the line. If you do that and are bluffing, and then waiver at the last second, your credbility is toast for other disputes, absent some higher than normal risk measures with the other relationships to prove that "We don't always bluff, just that time."
For the coerced party, haiving a deadline out there means that if negotiations are serious, put up or shut upon a deal that is reasonable, and then the negotiations will be finished by that date, or there will be war, a war that will by definition of coercer and coercee is likely to be a very destructive even for the lattert, e.g. a war between America and Iran.
Or, and more generally, if people at some point don't make this type of tacit ultimatum, it means people in this dispute have been bluffing the entire time, and have never had any intention of doing anything that different than what they were already doing.
Maybe that's the case with Iran's nuclear program, maybe not, but given electoral timetables it is fairly obvious that the bluff no bluff issue would be revealed in the next several months.
Given the consequences of underestimating the risks that it isn't a game of pure bluffing, that would suggest taking a proactive approach from the American side as to continuing to force the issue, including at some point pretty soon,putting out a date certain beyond which negotiations are not the instrument of American policy, but others are, e.g. violent means.
As to the functionality of deadlines in bargaining, just like at work, where having a time certain focuses activity, having a deadline focuses the bargaining on the reality that if bargaining by exchanges of notes is always preferable, at some point in State relations, that won't be the case, and the use of force will, as it always can, be the arbitration mode of the dispute.
Maybe Netanyahu's bluffing that he would really go it alone, and maybe the Persians are bluffing that they'd actually be a nuclear armed state, both to please "hawkish" domestic constituencies.
Then was would emerge is some face-saving deal where both sides can say "I was tough for you."
That's the policy argument for waiting and making them move first, and it's the one that is always popular in Dovish circles, and for understandable reasons.
On the other hand, if neither party is bluffing, and Ambassador Dennis Ross didn't think so as to someone who has good connections in both places, that's a recipe for us having to fight a war on other people's terms, and to have to fight a war around a core American national security interest in the process: Persian Gulf oil.
Persian Gulf oil was deemed a vital American security interest by President Carter in 1979, when he created CENTCOM to defend it, not so much because we get all our oil from there, which we don't, but because our allies do, who if cut off, would bid on oil we use, thereby having the same price effects at the spot margin, the spit price being important in determining prices even with the widespread use of long-term contractsin the oil industry.
China was an oil exporter then in 1979, and gets 500,000 barrels a day from Iran, as does Japan, as to the potential gravity of blowing something in that region, and something that argues for securing Iranian oil if you are going to really do that.
Unfortunately, Russia can't really quickly pick up a dramatic slack in oil production, and neither can we, although President Carter's creation of the Strategic Petroleum Reserve was of course exactly for this sort of contingency, and Libyan oil production could probably be increased somewhat, and there are alternate routes in Saudi Arabia that probably have a decent bit of emergency surge capacity for exactly this contingency.
Even with that, its pretty clear that any war between Iran and Israel would almost surely have dramatic implications for American national security interests, like it or not.
If it's the case therefore that we are really going down the line with Iran and its nuclear program, given electoral timetables here and in Israel, that means that we don't have a lot of time to make decisions.
Those decisions include: are we willing to make a time certain deadline, in which it is tacitly understood that there will be no more bargaining after that date, but an Ameircan bombardment that does serious damage to both the Iranian nuclear program, the regime, and some steps to secure what Iranian oil as we can to keep markets steady and bargain for favorable war termination.
April 13 is the next meeting between Iran and the Parties, more than two weeks.
We have been playing this game with Iran for a long time now, since 2002.
The North Korean example suggests that time isn't in the favor of trying to prevent an Iranian nuclear weapon.
History also suggests it's not easy to prevent any nuclear weapons program either, and look at Pakistan and North Korea for that proof.
Like they said in Pakistan, if people are willing to eat grass in order to have a nuclear weapon... they will probably end up with a nuclear weapon.
In fact, the former head of the Mossad has argued that all this pressure has made things worse, as the obviously elevated probability of an Israeli and/or American strike has incentivized Iran to rush with its clandestine efforts, although it's vital to note that he thinks any use of force would be a disaster, and vehemently opposes such a move, and has done so moreover in public at great personal risk in terms of a future in Israeli public life.
Clearly therefore, there are different views within Israel itself as to the wisdom of a military move,if maybe not among where it matters, Netanyahu's inner circle.
Tbis is just like there are probably differences within the Iranian regime as to the wisdom of taking the full step and testing and deploying a nuclear device on some set of available delivery vehicles, not necessarily in that order at this point, but in which again, what really matters is people who are rather opaque as to real intentions, to put it mildly.
As to how Iran would proceed, if you were them, you might well think that a nuclear test would instantly bring a bombardment down on your head, and not do that before going ahead and putting an untested design on a missile, and then testing and firing a missile opposite Israel as the signal that deterrence was now operative.
That might be a happy ending, if you think nuclear deterrence between those parties would hold, in which of course that question, "Will deterrence work between Iran and Israel," is the central problem at issue.
It would seem risky in general to keep adding more and more nuclear deterrent relationships too, in this case Saudi Arabia via Pakistan.
The Saudis funded the Pakistani program somewhat, and very, very indirectly to be fair, if on the theory of "If everyone else has a bomb, Muslims need one too."
Would that not tend to spread, and would that not tend to place more Russian and Chinese interests at stake too?
It's great to diffuse power in the international system, if you are Russia and especially with what is according to observers in The Nuclear Express the Chinese theory on this topic, right until there are too many relationships to manage by anything other than absract models of nuclear deterrence that miss local variations, and so therefore are more prone to errors that propoagate.
That is why in the theory of economics, there are firms, rather than all contractual relationships, per the economics of law.
It does make some states more powerful than others to limit the number of nuclear armed states, which puts a duty on those states to take other measures to make such relationships more palatable, because they are more just.
This is why if we are really going down the line with Iran, we need to have an offer that, even given cultural barriers, and especially conceptual barriers, is so obviously just, that only a non-rational actor would refuse, if a deadline is probably on balance important in that regard, if and only if, you are really serious, and are not just playing a sequence of bluffs and hoping everyone else is too.