Every few years, with soothing regularity, a prominent research institution comes along to recommend that the United States reengage with Iran. The gist of such reports usually follows the same line: Isolation just isn't working; reformists (or sometimes they're called moderates or pragmatists) need Washington's help in the battle against hard-liners; the country is not (nor will it ever be) on the verge of a new revolution; and only relations with the U.S. will provide incentives for better behavior.

This week, it was the Council on Foreign Relations that sounded the call in a 79-page report from a task force chaired by former national security advisor Zbigniew Brzezinski and former CIA Director Robert M. Gates.

Given the seriousness of the threat Iran poses, fresh ideas from the Council on Foreign Relations and elsewhere are, of course, welcome. Iran, after all, is Terror Central: It has become an operational headquarters for parts of Al Qaeda, continues to sponsor Hezbollah and Hamas, and senior officials remain under indictment in U.S. court for masterminding the 1996 bombing in Saudi Arabia of the Khobar Towers military housing complex, in which 19 Americans died. According to U.S. and European officials, the regime also remains bent on acquiring nuclear weapons and is well down the road to doing so.

Clearly, U.S. policy in Iran has been a failure. Its problems have persisted notwithstanding four years of tough talk from the Bush administration, a continued embargo on U.S. investment and virtual diplomatic radio silence. It's time to try something new; on that much, we can agree with the pro-engagement groups.

But that's where our agreement ends. They insist, in the face of evidence to the contrary, that dialogue and trade would succeed where a hard line has failed. Yet dialogue and trade are the hallmarks of Europe's fruitless engagement of Iran. Neither European diplomatic outreach nor cordial trading relations have achieved results. Carrot-and-stick offers, like a proffered "trade and cooperation agreement" in exchange for a stand-down on nuclear proliferation, have also failed. Engagement is a proven bust.

The fact is, neither tough love nor tough talk will achieve results in Iran because decision-makers in the government--not just the so-called hard-liners but the "moderates" and "pragmatists" as well--are committed to supporting terrorism, developing nuclear weapons and annihilating Israel. Any opening from the U.S. will only lend credibility to that government and forever dash the hopes of a population that, according to reliable polls, despises its own leadership.

So what to do? President Bush has taken the first step by making clear that the Iranian clerical regime is anathema to the U.S. national security. But we're not likely to invade for a variety of practical reasons, among them a shortage of troops and an absence of targeting information about Iran's nuclear sites. Nor can we count on Iran's weary and miserable population to rise up unaided and overthrow its oppressors; virtually all analysts agree that's not about to happen.

Instead, a new three-part policy is needed.

First, the administration must ante up promised support for the Iranian people. Just as we supported Soviet dissidents, we must use the diplomatic and economic tools at our disposal to embarrass the regime for its abysmal human rights abuses, rally behind dissident student groups and unions and let them know that the U.S. supports their desire for a secular democratic state in Iran.

Second, the administration must persuade the European Union and the International Atomic Energy Agency to stand firm in their confrontation over Iran's nuclear program. Iran has made commitments to end the production and assembly of nuclear centrifuges. It has reneged on those promises, and the next step is for the IAEA to refer the matter to the U.N. Security Council. There is quiet talk of economic sanctions in European capitals; the EU must know that a failure to follow through would mean an Iranian nuclear weapon within a few years.

Finally, the U.S. must lead in the containment of Iran. Iranian weapons imports and exports should be interdicted; financial transfers to terrorists must be identified and confiscated; terrorists traveling into and out of Iran should be aggressively pursued and eliminated.

These steps would not deliver quick solutions, but they are the only rational course available to the U.S. and its allies. We have seen that engagement with the current leadership of Iran would not achieve policy change; all it would do is buy an evil regime the time it needs to perfect its nuclear weapons and to build a network of terrorists to deliver them.

Danielle Pletka is vice president for foreign and defense policy studies at the American Enterprise Institute.