Updated October 29, 2020
Iran’s Nuclear Program and U.N. Sanctions Reimposition
U.N. Security Council Resolution 2231 (2015), which the
The NPT, which Iran ratified in 1970, includes prohibitions
council adopted on July 20, 2015, implements the Joint
on obtaining or producing nuclear weapons.
Comprehensive Plan of Action (JCPOA) and contains other
Comprehensive safeguards agreements are designed to
provisions concerning Iran’s nuclear program, Tehran’s
enable the agency to detect the diversion of nuclear material
development of missiles, and arms transfers to and from
from declared nuclear facilities, as well as to detect
Iran. The United States has invoked the resolution’s
undeclared nuclear activities and material. (See CRS Report
“snapback” mechanism, which requires the Security
R40094, Iran’s Nuclear Program: Tehran’s Compliance
Council to reimpose U.N. sanctions lifted pursuant to
with International Obligations, by Paul K. Kerr.)
Resolution 2231 and the JCPOA.
Iran is also implementing the Additional Protocol to its
The JCPOA, finalized in July 2015 by Iran and China,
comprehensive safeguards agreement. Such protocols
France, Germany, Russia, the United Kingdom, and the
increase the IAEA’s ability to investigate undeclared
United States (collectively known as the P5+1), requires
nuclear facilities and activities in nonnuclear-weapon states
Iran to implement constraints on its uranium enrichment
by increasing the agency’s authority to inspect certain
and heavy water nuclear reactor programs, as well as allow
nuclear-related facilities and demand information from
the International Atomic Energy Agency (IAEA) to monitor
member states. Pursuant to its JCPOA commitments, Iran is
Tehran’s compliance with the agreement. Prior to the
implementing provisionally its additional protocol; Tehran
JCPOA, these programs caused international concern
is to seek ratification of the protocol by the Iranian
because they could both have produced fissile material for
parliament no later than October 2023. Iran originally
use in nuclear weapons.
signed such an additional protocol in late 2003, but stopped
Pursuant to the JCPOA, Tehran received relief from
implementing it in early 2006.
sanctions imposed by the European Union, United Nations,
The IAEA also continues to monitor JCPOA restrictions,
and United States. On the agreement’s January 16, 2016,
which supplement Iran’s safeguards obligations and
Implementation Day, the Security Council terminated
prohibit Iran from engaging in a number of dual-use
sanctions imposed by three previous resolutions on Iran; the
“activities which could contribute to the development of a
council adopted the first of these resolutions (1996) in 2006
nuclear explosive device.” Should the JCPOA be
and the last (1929) in 2010. The sole operative Security
implemented as envisioned in the agreement, most of its
Council resolution concerning Iran’s nuclear program,
nuclear-related restrictions will expire. In that case,
Resolution 2231, also stipulates that the council, which has
Tehran’s nuclear program will be governed indefinitely by
been seized of the “Iranian nuclear issue” since 2006, is to
Iran’s obligations pursuant to the NPT, the government’s
end its consideration of the matter in 2025. The resolution’s
IAEA comprehensive safeguards agreement and Additional
snapback mechanism will then cease to be operational.
Protocol, and the dual-use restrictions described above.
In May 2018, President Donald Trump issued a
U.N. Security Council Resolution 2231
memorandum stating that the United States would no longer
(2015) and Snapback
participate in the JCPOA and would reimpose sanctions that
In addition to its JCPOA-related provisions, Resolution
had been suspended pursuant to the agreement. Arguing
2231 imposes other requirements on Iran. For example, the
that subsequent efforts by the remaining JCPOA
resolution restricts exports of missile-rated items to Iran
participants, known as the “P4+1,” were inadequate to
until October 2023; other restrictions concerning Iranian
sustain the agreement’s benefits for Iran, the government
imports and exports of conventional weapons expired on
has undertaken some nuclear activities that exceed JCPOA-
October 18, 2020. Despite lacking a direct connection to the
mandated limits. Iranian officials continue to assert that
country’s nuclear program, previous arms restrictions, the
Tehran will resume implementing all of its JCPOA
first of which were imposed by Security Council Resolution
commitments if the P4+1 does so.
1747 (2007), were part of a broad U.S.-led approach of
Iran’s Nuclear Program and Selected
pressuring Iran to comply with relevant council resolutions.
JCPOA Provisions
(For more on the arms restrictions, see CRS In Focus
Although some Iranian nuclear activities exceed JCPOA-
IF11429, U.N. Ban on Iran Arms Transfers and Sanctions
mandated limits, other aspects of the country’s nuclear
Snapback, by Kenneth Katzman.)
program still comply with those limits. Tehran has
According to Resolution 2231, a JCPOA participant can,
continued to allow IAEA monitoring of Iran’s JCPOA
after notifying the Security Council of an issue that the
commitments, which supplement Tehran’s obligations
government “believes constitutes significant non-
pursuant to its IAEA comprehensive safeguards agreement
performance of [JCPOA] commitments,” trigger an
and the nuclear Nonproliferation Treaty (NPT).
automatic draft resolution keeping sanctions relief in effect.
A U.S. veto of this resolution would both reimpose the
suspended sanctions and end expiration of the conventional
https://crsreports.congress.gov
Iran’s Nuclear Program and U.N. Sanctions Reimposition
arms and missile-related export restrictions, as well as
Council to adopt “measures not involving the use of armed
Security Council consideration of the Iranian nuclear issue.
force,” including sanctions, “to give effect to its decisions”
concerning “threats to the peace, breaches of the peace, and
Whether the United States has the status to invoke
acts of aggression.”
Resolution 2231’s snapback mechanism is under debate.
Since adopting Resolution 1737 in
The JCPOA lacks a withdrawal clause, and no Security
2006, the council has been considering the Iranian nuclear
Council resolution has altered the U.S. status as a JCPOA
issue pursuant to Article 41. Iranian officials have touted
“participant.” Resolution 2231 is silent on the mechanism’s
the end of this status, which, as noted, Resolution 2231
status in the event that a P5+1 government ceases
stipulates.
implementing its JCPOA commitments. The United States
Iranian statements and the JCPOA text indicate that the
neither describes itself nor acts as a JCPOA participant. Not
government may stop performing all or some of its JCPOA
only does the May 2018 memorandum mentioned above
commitments if the Security Council extends the above-
describe a U.S. decision to end its “participation” in the
mentioned arms restrictions or invokes snapback. If Iran
agreement, but the United States is also no longer
were to end its JCPOA participation entirely, the
performing its JCPOA commitments.
government would be bound only by its comprehensive
Paragraph 10 of Resolution 2231 names the P5+1 countries
safeguards agreement, which is of indefinite duration. Iran
as “JCPOA participants.” But it is not clear that
would not be bound by its Additional Protocol, should
“participants” is meant to include a P5+1 government that
snapback occur before Iranian ratification of that
ceases performing its JCPOA commitments, or if the term
agreement.
merely identifies the JCPOA participants in July 2015.
In such a scenario, the IAEA would retain its monitoring
Notably, the agreement describes the P5+1 as “participants”
and inspection authority pursuant to Iran’s comprehensive
when naming those states as members of the JCPOA-
safeguards agreement, but the scope of this authority would
established joint commission. The United States no longer
be narrower. For example, the agency would no longer be
participates in that commission’s activities.
able to monitor certain Iranian facilities that do not contain
In an August 20 letter to Security Council President
nuclear material but are associated with the government’s
Indonesian Ambassador Dian Triansyah Djani, Secretary of
enrichment program. The IAEA would also retain its
State Michael Pompeo initiated the snapback process by
authority to verify the absence of undeclared nuclear
notifying the council that Iran “is in significant non-
material and activities, but the agency would have fewer
performance” of its JCPOA commitments. This action
means to do so, if Iran’s additional protocol is not in force.
followed the council’s rejection of a U.S.-sponsored draft
Moreover, Tehran would not be bound by any constraints
resolution to extend Resolution 2231’s conventional arms-
on its enrichment program, which has been the main source
related prohibitions. The letter argued that the Resolution
of proliferation concern, although Iran would remain bound
2231 language cited above gives the United States the right
by its NPT obligations. Significant expansion of Tehran’s
to invoke snapback. The P4+1 Governments rejected this
enrichment program would likely decrease the amount of
claim. Moreover, Djani explained in an August 21 letter to
time necessary for Iran to produce enough weapons-grade
the council that Pompeo’s letter “has no legal effect.” But
highly enriched uranium for use in a nuclear weapon.
Pompeo stated on September 19 that “the snapback of
Prior to the JCPOA, Iran was improving its ability to
previously terminated UN sanctions…became effective”
produce fissile material, despite U.N. and other sanctions’
that same day.
evident success in slowing the nuclear program. At the
UN Secretary General António Guterres wrote in a
time, knowledgeable IAEA and U.S. officials observed that
September 19 letter that the “majority” of Security Council
IAEA safeguards on Iran’s declared nuclear facilities would
members have that Pompeo’s letter did not constitute” the
likely have detected an Iranian attempt to use them for
notification necessary for snapback, The resulting
producing nuclear weapons. (For more information, see
uncertainty, he added, requires the Secretary to refrain from
CRS Report RL34544, Iran’s Nuclear Program: Status, by
proceeding on the matter. The Security Council could send
Paul K. Kerr.) Nevertheless, Iran’s continuing nuclear
the issue to the International Court of Justice for an
program concerned many governments. Indeed, U.S. and
advisory opinion, but the council lacks an independent
Israeli officials at the time planned for a possible attack on
mechanism to adjudicate these sorts of claims, and council
Iran’s nuclear program to prevent Tehran from developing a
members typically reach political settlements to resolve
nuclear weapon. The end of Iranian JCPOA participation
such disputes. The implications of a council failure to reach
could beget a similar situation.
such a settlement in this case are unclear.
Iranian officials have indicated that the government might
Possible Iranian Responses
withdraw from the NPT in response to snapback; the treaty
In addition to reimposing sanctions, snapback would
has a withdrawal provision. In this case, Tehran would not
remove other incentives for Iran to continue participating in
be bound either by its comprehensive safeguards agreement
the agreement. These incentives include expiration of the
or by its treaty obligations. Notably, these Iranian officials,
restrictions on Iranian arms-related imports and exports, as
echoing a long-standing government position, have stated
well as missile-related imports described above.
that Tehran would still refrain from producing nuclear
weapons. Iran’s Foreign Ministry warned in an October 18
Snapback would also end the process by which the Security
statement that Tehran “reserves the right to take any
Council is to end in 2025 its consideration of the Iranian
necessary countermeasures to secure its national interests”
nuclear issue. The council adopted all of the resolutions that
in response to states’ violations of Resolution 2231.
imposed sanctions on Iran, as well as Resolution 2231,
under Article 41 of Chapter VII, which enables the Security
Paul K. Kerr, Specialist in Nonproliferation
https://crsreports.congress.gov
Iran’s Nuclear Program and U.N. Sanctions Reimposition
IF11583
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