Every 90 days, the State Department must certify whether Iran is complying with the nuclear deal that former President Barack Obama struck with the Tehran tyranny in 2015.

Secretary of State Rex Tillerson is approaching one of these 90-day deadlines. Instead of rubber-stamping re-certification, as his predecessor John Kerry did regardless of Iran's behavior, Tillerson should finally do something the U.S. government hasn't been doing for years. He should tell the truth about Iran's flagrant noncompliance with the deal, thus opening the way for Congress to impose sanctions against the rogue regime.

This is what four Republican senators — Tom Cotton, R-Ark., Ted Cruz, R-Texas, Marco Rubio, R-Fla., and David Perdue, R-Ga. — urged him to do this week.

In their letter, the senators restated what has been obvious for more than a year. Iran has trampled all over the terms of the deal struck by the ducking and bowing Obama administration. The agreement itself stipulates that the mullahs should be punished for their recalcitrance. If the administration keeps turning a blind eye to Iran's transgressions, as Obama did, the world's leading state sponsor of terrorism will continue its belligerence with a free hand.

Iran's progress toward nuclear weapons and missile technology is unabated. It is, for example, operating more centrifuges than it agreed to with Obama, and storing more heavy water (composed of oxygen and the rare, heavy hydrogen isotope called deuterium) than is allowed.

Most importantly, it has refused to give inspectors access to its nuclear facilities. There can obviously be no "trust and verify," because if verification is blocked there is ample reason to mistrust. There may be many other violations of which Washington is unaware. Indeed, it seems highly likely.

"In light of Iran's malign actions since the signing of the [nuclear deal]," the senators wrote, "the only reasonable conclusion is that the full suspension of U.S. sanctions is not in the vital national security interests of the United States and that Iran has consistently violated the terms of the [nuclear deal]."

Iran's other malicious activities, such as its sponsorship of terrorist militias throughout the Middle East and its abduction of Americans in search of ransom, should also weigh heavily in the scales as the administration's assesses the best move to make next. Obama overlooked all these things to get a deal with Iran, in the irresponsibly fantastical belief that Tehran could become a strategic partner in the region. He was so committed to having a deal that he sacrificed much of what might have made some sort of deal worthwhile.

Tillerson has not committed to anything yet, but has sent the right signs that he knows what must be done. The last time he was required to recertify Iranian compliance, it was widely understood that he did so only to maintain the status quo temporarily at the inception of Trump's presidency.

Despite that initial recertification, he publicly disparaged Obama's lax approach to the deal even as he recertified Iranian cooperation. "Strategic patience is a failed approach," Tillerson said in April. "The Trump administration has no intention of passing the buck to a future administration on Iran."

Those are good, strong words. Now, it's time for Tillerson to back them up with actions and hold Iran accountable.