Five Months Later: Why the Iran Strikes Still Threaten U.S. Security

The DHS warning was never about the days that followed, but the dangerous months after, when retaliation matures, vigilance fades, and delayed threats take shape.

On June 22, 2025, the U.S. Department of Homeland Security issued a National Terrorism Advisory System bulletin warning that the United States had entered a heightened threat environment following a series of dramatic military events involving Iran. The alert was triggered not by a singular incident, but by a rapid escalation in conflict: Israel’s June 13 air campaign against Iranian military and nuclear targets, followed by the United States conducting its own airstrikes on three Iranian nuclear facilities on the evening of June 21. Although these events now lie five months behind us, the threat landscape that prompted the bulletin has not expired. On the contrary, the long-term nature of retaliatory planning, global radicalization dynamics, and Iran’s established pattern of external operations suggest that the risk today may be more mature, not less.

Israel’s June 13 air operation marked one of the most significant direct attacks on Iranian military and nuclear infrastructure in years. Additional reporting indicates that the strikes killed hundreds of Iranian personnel and severely disrupted key military facilities. Israel has claimed that its campaign severely degraded Iran’s operational capability. Iranian officials called the assault an act of war, and issued multiple vows of retaliation across different fronts. United States forces entered the picture eight days later, when Washington launched an airstrike against three Iranian nuclear sites on June 21. President Trump stated that the strikes were intended to halt Iran’s nuclear escalation and warned Tehran that further retaliation would be met with additional military action.

The following day, DHS issued its nationwide terrorism alert. The bulletin cited the escalating Israel–Iran conflict, Iran’s demonstrated history of conducting external covert operations, and the risk of retaliatory activity targeting the U.S. homeland. DHS emphasized that both foreign terrorist actors and domestically radicalized individuals might be motivated or enabled by the conflict to attempt attacks. The advisory noted that there had been no specific, credible plot identified at that time, but nevertheless warned that the situation required elevated vigilance due to the shifting threat environment.

Critical to understanding the bulletin is recognizing that it was not released as a response to specific intelligence pointing to immediate attacks in late June. Rather, it was issued as a recognition that the conditions were forming for increased risk over an extended period. Terrorism studies consistently show that the most significant threats often emerge months after high-profile geopolitical shocks, especially when state or non-state adversaries seek to retaliate strategically. The bulletin reflected this timeline. DHS warned that Iran and its proxy elements have a history of conducting surveillance, cyber intrusions, assassination attempts, and targeted external operations abroad, and that multiple such plots had been disrupted on U.S. soil since 2020. DHS and intelligence-community reporting further indicated the likelihood of increased cyber activity targeting U.S. infrastructure by actors affiliated with Iran.

Recent academic assessments add important depth to this context. A comprehensive study published by the Combating Terrorism Center at West Point in 2024 documented Iranian-linked external plots in numerous countries, including the United States, over the last decade. Intelligence summaries, as well as previous Department of Homeland Security threat assessments, have similarly identified Iran as a capable external actor when motivated by perceived existential threats or high-profile provocations. Historically, Iran’s retaliatory strategy favors indirect and asymmetric approaches, including cyber operations, targeted attacks against dissidents, proxy-actor involvement, and episodic terrorist plots abroad.

Cybersecurity professionals also warn that the cyber dimension of this threat has expanded significantly in the last two years. High-profile cyber incidents in 2024 and 2025 linked to state-level actors have demonstrated how disruptive cyber retaliation can be. Multiple independent analysts have noted that escalating military conflict in the Middle East has increased the likelihood of cyberattacks targeting U.S. and allied commercial infrastructure. This aligns with DHS’s bulletin guidance directing heightened monitoring by critical-infrastructure operators.

Although the NTAS bulletin issued in June was largely overshadowed by the news cycle at the time, several state emergency management offices republished and amplified the advisory, noting that the heightened threat environment was expected to continue through late September 2025 and could be extended beyond that period based on evolving conditions. It is significant that the bulletin was not rescinded at the conclusion of the initial timeframe. Instead, federal officials signaled that the risk period had not closed.

Because five months have passed since the strikes, many people understandably assume that the danger has diminished. In reality, counterterrorism professionals emphasize that retaliation unfolds slowly. State-linked actors, and networks influenced by state-linked actors, typically operate on months-long planning timelines. Cyber planning, operational reconnaissance, facilitation, financing, logistical preparation, and target identification take time. Physical operational planning is slow, largely compartmentalized, and dependent on opportunity, not immediacy. There is also a relevant psychological factor: public vigilance tends to decrease several months after a major geopolitical event, which paradoxically can increase risk.

In addition, intelligence services historically observe seasonal and symbolic timing patterns. High-profile attacks or attempts are more likely to occur near national holidays, anniversaries, elections, or symbolic dates. For this reason, geopolitical shocks in early summer often produce operational consequences in late fall or early winter. The United States currently sits inside that window.

Second, online radicalization does not unfold instantly. It builds over time. As the conflict has continued, analysts have documented increases in extremist messaging online inspired by regional events. In the past, lone actors motivated by geopolitical grievances have conducted attacks in the United States months after triggering events faded from mainstream public consciousness. DHS noted this danger explicitly in its bulletin.

Third, Iran’s strategic position has not changed. It continues to frame the June strikes as severe aggression. Internal messaging from Iran’s leadership continues to emphasize retaliation as a matter of national honor and religious responsibility. Tehran has historically demonstrated willingness to pursue external action for far less significant provocations than direct strikes on nuclear sites.

Fourth, the cyber threat remains acute. Cyber threat intelligence firms have indicated that probing behavior linked to Iranian-aligned actors has continued in waves since June. Cyber probing campaigns targeting infrastructure and commercial networks do not usually produce immediate visible effect. It is the lateral movement that follows initial reconnaissance that produces material consequences.

Finally, threats remain relevant as long as the underlying geopolitical conflict remains unresolved. Israel’s campaign against Iran has continued episodically. Iran’s regional proxies have fluctuated in activity, but none have disarmed. The conflict remains active, and tensions remain elevated.

The enduring relevance of the June advisory lies not in the events themselves, but in what those events set into motion. Time did not close the window. Time matured it.

Understanding this distinction is crucial for the general public. The National Terrorism Advisory System is not a tool designed to create panic after a single event. It is a system designed to warn about shifts in the long arc of risk. That arc did not end when the headlines faded. It entered a new phase.

While direct action by the general public is limited, there are practical implications. Awareness remains the first line of defense. Individuals should remain attentive to unusual behavior around critical or symbolic locations. Businesses, particularly those with potential vulnerabilities, should ensure cybersecurity protocols remain active and current. Institutions with symbolic or cultural significance should continue to maintain prudent security protocols and coordination with local law enforcement. Federal and state authorities have encouraged the public to report suspicious activity, especially in the context of geopolitical escalation.

Five months on, the threat today is defined not by urgency, but by complexity. The most significant consequences of June’s events may not have manifested yet. Retaliation is most often slow, asymmetric, and opportunistic. The success of the nation’s counterterrorism posture depends as much on long-term vigilance as on immediate reaction. The real measure of public security is not whether instantaneous threats arise, but how resilient society remains while adversaries wait for the opportunity they prefer, not the moment we expect.

The June 2025 DHS bulletin warned Americans about an environment shaped by evolving, not static, danger. That warning remains relevant precisely because time has passed, not in spite of it. As public attention shifts to new stories, the underlying strategic realities remain. It is within this quiet space—between memory and consequence—that vigilance matters most.

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REFERENCES

CBS News. (2025, June 23). Homeland Security warns of heightened threat environment after U.S. strikes three Iranian nuclear facilities. CBS News.

Combating Terrorism Center at West Point. (2024). Tehran’s homeland option: External operations and strategic retaliation risk. CTC, U.S. Military Academy.

Department of Homeland Security. (2024). Homeland Threat Assessment 2025. U.S. Department of Homeland Security.

Department of Homeland Security. (2025, June 22). National Terrorism Advisory System Bulletin. U.S. Department of Homeland Security.

Oregon Office of Emergency Management. (2025, June 24). State advisory summary: Heightened threat environment. Oregon OEM.

Trustwave SpiderLabs. (2025, June). Cyber threat trends: Escalation patterns in Middle East conflict. Trustwave Holdings.

United States Cybersecurity and Infrastructure Security Agency. (2025). Cyber activity linked to Iranian-affiliated threat actors: Infrastructure alert summary. CISA.

Washington Post. (2025, June 17). Israel strikes Iran in largest aerial campaign in over a decade, officials say.

Source: http://terrorism-online.blogspot.com/2025/11/five-months-later-why-iran-strikes.html