It seems likely the Trump administration may decide to renegotiate the terms of the Iranian nuclear accord by "decertifying" it. This would start the clock on possibly reimposing U.S. sanctions on Iran that were lifted as the U.S part of the nuclear deal with Iran two years ago. At that time, Iran was within 30 days of producing several nuclear warheads. Today, it would take Iran about a year to regroup and build the same warheads, assuming President Hassan Rouhani keeps his word not to renegotiate if America breaks the accord.

If the United States were unsuccessful at renegotiation and the countries withdrew from the nuclear accord, there would then be two new nations with a nuclear weapon capability to reach America: North Korea and Iran. The U.S. ability to shoot down one intercontinental ballistic nuclear missile launched from either of these countries is at best 50-50. However, the alternative to stopping Iran from having the nuclear bomb is a U.S. military strike on Iran's nuclear and missile infrastructure.

Our military can do it. But first, our aircraft carriers must depart the Persian Gulf, where Iran's 20-plus submarines lurk undetected and where hundreds of anti-ship missiles sit ashore, ready to be fired from a few miles away. Moreover, our aircraft carriers can operate in only two small areas deep enough to permit sailing safely 30 minutes in one direction to launch aircraft every hour. Consequently, the Iranian midget submarines can sit on the gulf bottom in those two areas, waiting for the carriers to come near them, knowing they are virtually undetectable by U.S. sonar.

By the time we begin the strikes from outside the Persian Gulf, the Strait of Hormuz will be closed by thousands of mines laid by Iranian fishing vessels. That would effectively bottle up 20 percent of the world's oil supply in the gulf, while playing havoc with the global economy outside it. After the weeks —  months — needed to do the strikes, it will take additional weeks to then clear the strait safely. The length of time is based on the likelihood that the aircraft carriers will assume a disproportionately heavy share of the strikes if regional nations don't permit U.S. air bases on their territory to be used against Iran.

The initial U.S. strike priority will be the fairly sophisticated air defense systems Iran has purchased, partly from the Russians, so follow-up strikes by aircraft can proceed safely. Meanwhile, not only are hundreds of anti-ship missiles and combat aircraft being launched, but so are hundreds of Shahab ground missiles that will hit U.S. military bases in the region, and that will also strike Israel. These missile sites demand destruction, too, before proceeding against Iran's nuclear infrastructure weeks later.

Iran is not Iraq for any comparable U.S. strike assessment: Iran is four times larger, permitting wide dispersal of military assets; it has more sophisticated weapons systems; and it has offensive naval, air, missile, and special forces capabilities. In addition, Iran's nuclear production facility is not only broadly distributed but also deeply buried and hardened. Though nuclear facilities at Natanz, Tehran, Esfahan, and Arak may be impaired and destroyed, it is likely the Fordow enrichment facility may only be damaged because it is under 200 to 300 feet of rock.

In short, the United States can neutralize the nuclear production facilities of Iran, with great consequential damage to its military capability, by a sustained air and missile attack of several months — but in about four years, Iran will have rebuilt the facilities. Our successful strikes will have brought about destructive Iranian retaliation on U.S. regional forces and Israel, forfeiture of an international alliance against Iran's nuclear capability, unsettling global economic instability, and the likelihood that Iran will become a nuclear power — unless struck again.

Iran should not be permitted to be a nuclear weapon power. The nuclear accord has achieved this, and Iran has adhered to it. To break the deal is to permit what has been described above. Keep in mind: Though militaries can stop a problem, they cannot fix a problem. But the nuclear accord has done just that. If the Trump administration plans to break that nuclear deal, the public should know both the military and economic challenges and costs of stopping, not fixing, the Iranian pursuit of nuclear weapon capability. Only then can they best decide whether the administration's actions are necessary.

Joe Sestak is a former Navy admiral and U.S. congressman.