The April 2 nuclear framework agreement with Iran raises a host of questions about national security strategy, nuclear diplomacy, domestic politics here and in Iran, and the broader politics of the Middle East. The role and efficacy of financial sanctions in curbing Iran’s nuclear-related programs also have been widely debated in the last several weeks.

The structure of the talks since 2013 seems to answer questions about the efficacy of sanctions in the Iran context rather clearly. The core question in the talks has always been: What level of sanctions relief would the P5+1 offer in exchange for which types of concessions on Iran’s nuclear program?

But persistent questions about whether sanctions “worked” with respect to Iran specifically reveal three larger questions about the nature and purpose of financial sanctions more generally. As sanctions play a larger role in a range of security situations, and with the United States unveiling a new cybersecurity sanctions program just last week, these tectonic questions call for more robust public debate and discussion.

How do we understand the purpose of financial sanctions?

Financial sanctions are regulatory measures imposed on US citizens and companies that restrict them from engaging in certain conduct. These restrictions are imposed in service of a larger foreign policy objective — generally speaking, to impede illicit activity, to contain threats, or to change behavior (or, sometimes, all of those objectives at once). Sanctions are, therefore, tools of risk management, not tools aimed at achieving decisive outcomes and resolving conflicts by themselves. Framed in this way, the question of whether a specific sanctions program “worked” must be answered with reference to the specific goal the sanctions program was designed to achieve.

In the Iran case, robust sanctions were imposed in order to generate pressure to get Iran to the negotiating table and to keep it there, engaging in good faith negotiations with the P5+1 about its nuclear program.  Prior to 2007, when the US sanctioned an Iranian bank for the first time, Iran enjoyed nearly unfettered access to the world’s premiere financial centers. Today, however, Iran finds itself almost entirely frozen out of the international financial system, unable to sell oil in significant quantities, and unable to access foreign currency reserves held in banks outside the Islamic Republic because of various US statutes and executive orders. Indeed, Iran has found it difficult to conduct even the transactions permitted by the Joint Plan of Action, which offered Iran limited sanctions relief and structured negotiations from November 2013 until the framework agreement was announced last week. That’s leverage.

But once Iran got to the table, nobody was certain that a deal would be achievable (indeed, some of the most difficult negotiations about the detailed implementation structure for the agreement remain ahead). The sanctions at issue in the negotiations were not designed to force Iran to unilaterally capitulate and abandon its nuclear ambitions. They also were not designed to resolve much larger questions about Iran’s role in the region, its support for global terrorism, or its atrocious human rights record.

We may find ourselves in a position several months from now in which the P5+1 and Iran were unable to reach a final agreement resolving the dispute about its nuclear program. But that does not necessarily mean that sanctions failed. Rather, it means that the maximum concessions Iran was willing to make with its enrichment program were less than the minimum concessions the P5+1 was willing to accept in exchange for sanctions relief. Evaluations of the efficacy of sanctions, therefore, must be based on nuanced determinations about the goals sanctions were imposed to achieve — in this case, getting Iran to the table, but not necessarily ensuring any particular outcome once it arrived.

How do we conceptualize metrics for evaluating effectiveness?

It is fairly easy to measure the economic effects of sanctions. The values of the (Russian) Ruble and (Iranian) Rial have dropped dramatically since sanctions were imposed in each instance. So too have the foreign currency reserves of each country. But are these the right ways to measure effectiveness? How do we know what the right metrics are? The real question is whether we understand the transmission mechanisms between the specific sanctions measures imposed and the behaviors among foreign leaders and non-state actors that we are trying to change.

The way in which sanctions exert pressure to affect change will, necessarily, be different in each case, and sanctions programs are designed with these differences in mind. That is why sanctions programs in the context of nations like Venezuela, Iran, North Korea, and Russia all look different. And it’s why the new sanctions program targeting “Significant Malicious Cyber-Enabled Activities” isn’t the same as sanctions programs targeting terrorism and narco-trafficking. But we need a more robust public dialogue about how the effectiveness of sanctions should be measured, and more work to understand the transmission mechanisms between the specific sanctions measures imposed and the behaviors among foreign leaders and non-state actors that we are trying to change.

How do sanctions fit into holistic approaches to strategic problems?

Sanctions cannot unilaterally solve foreign policy problems; they must be integrated with other tools of national power into a holistic strategic approach to threat management. The Iran nuclear negotiations are perhaps the best example of how this can be done — the sanctions programs were tied tightly to the concept or conduct of a diplomatic process and focused on generating leverage that would be deployed in those negotiations. But this should be true across sanctions programs, from those levied against Russia in response to its aggression in Ukraine, to those contemplated in the cybersecurity context.

With those larger points in mind, the real test of the Iran negotiations will come only in June, when a detailed final agreement between Iran and the P5+1 is set to be concluded. But already the Iran case has proven instructive on many facets of the sanctions discussion, and will provide fruit for analysis well into the future.