Stephen Carter says “probably nothing” is what happens if Iran cheats on the nuke deal:
Let’s take an example. Under the action plan, Iran is permitted to enrich uranium only at its Natanz facility, and only up to 3.67 percent, well below weapons-grade. Suppose that a few years down the road, once things are humming along, the U.S. discovers, through its fabled if imperfect “national technical means,” that Iran has illegally established a second enrichment site apart from Natanz. The U.S. thinks that the regime is using its new, secret facility — we’ll call it Site X — to enrich uranium up to 5 percent, a range not uncommon in light water reactors. This figure would not be sufficient to produce weapons-grade fissile material, but it would still exceed the 3.67 percent allowed under the agreement.
Now what happens?
Presumably the U.S. passes the information along to the IAEA inspectors. The next part of the process is guided by Part Q of Annex I of the action plan. Under paragraph 75, the IAEA will ask Iran for “clarification.” If the explanation is not satisfactory, paragraph 76 allows the inspectors to “request access” to Site X. Paragraph 77 entitles Iran to offer an “alternative means” rather than inspection to resolve the issue.
Cheating is a feature, not a bug — and the White House and State Department know it.