The distance between peace and conflict with Iran is now best measured by a number, 16.33%.

That's the difference between the level to which Iran is currently enriching its uranium, and the percentage it is threatening to enrich to beginning next week. Why does that matter?

Well, because while Iran's enrichment level currently stands at 3.67%, if it goes beyond 20%, it will be able to produce a nuclear weapon. That's a difference of 16.33%. The stakes are clear.

Iranian President Hassan Rouhani warned on Wednesday that if the European Union fails to provide sanctions relief to Tehran, "The level of Iran's enrichment will not be limited to 3.67% anymore ... we will enhance the level to the extent we need." Considering that the European Union cannot satisfactorily address Iran's concerns, we should expect Tehran's enrichment policy to escalate next week.

At that point, the Europeans will have to decide whether to keep appeasing Iran or to address its brinkmanship by supporting renewed sanctions. If the Europeans choose the sanctions route and Iran realizes its options are limited, the regime will face a binary choice between implosion and new negotiations. If, however, Iran decides to increase its enrichment level beyond 20%, the U.S. and Israel will face a critical choice.

Because then Iran will be just a few months away from a viable nuclear weapon. And advanced Iranian ballistic missile research means we must also assume some risk that Iran can platform a nuclear warhead onto a missile. That threat will cross Israeli red lines but also pose an imminent threat to Saudi Arabia, and U.S. forces across the Middle East. It will thus be a casus belli for a massive air and missile campaign against Iran.

President Trump must make clear that Iran's current course will lead the regime nowhere good. He must ensure that Iran's leaders, especially Ayatollah Khamenei, realize that action against U.S. interests or in pursuit of nuclear weapons will meet an overwhelming response. And Trump must clarify that his only demand is Iran's return to the nuclear negotiating table.

The immediate stakes are greater than many assume.