According to a recently published report by a scholar at the Marine Corps University, Islamic State (IS) and perhaps even al-Qaeda, having been driven from their territorial strongholds, are likely to take up campaigns of maritime terror. IS successfully carried out an attack on an Egyptian navy frigate, using anti-ship missiles, in the summer of 2015. Michael Rubin explains what could be next:

[T]he Arabs and the Islamic world more broadly have a long and rich maritime legacy, one in which the symbolism-conscious Islamic State can find inspiration. . . .

[The] al-Qaeda military strategist Abu Ubayd al-Qurayshi first sought to integrate maritime operations into a broader jihadist strategy. Al-Qurayshi argued that doing so was especially important to achieve the goal of undermining the U.S. economy, given the importance of trade and the freedom of navigation. . . .

How might al-Qaeda and Islamic State act in the future? In short, they hope to entice the U.S. Navy into narrow waterways off the coast of hostile regions, such as the waters off Yemen and Somalia [as well as] Libya, Egypt, and Syria, and in the Straits of Malacca and the South China Sea. While ships have grown accustomed to treading carefully off the Horn of Africa, Yemen is more difficult to avoid: the Mandeb Strait between Yemen and Djibouti is a chokepoint that shipping transiting the Suez Canal cannot avoid. The same holds true with the Straits of Malacca, especially if extremists succeed in their efforts to gain footholds in Indonesia.

As for the Mediterranean, the development of local gas fields and the rise of Islamic State proxies along its shores mean that it is in play in a way that it has not been since the cold war.

Surveying news websites and social media on Sunday morning, I immediately found some intelligent and well-informed observers arguing that Iran deliberately warned the U.S. of its pending assault on Israel, and calibrated it so that there would be few casualties and minimal destructiveness, thus hoping to avoid major retaliation. In other words, this massive barrage was a face-saving gesture by the ayatollahs. Others disagreed. Brian Carter and Frederick W. Kagan put the issue to rest:

The Iranian April 13 missile-drone attack on Israel was very likely intended to cause significant damage below the threshold that would trigger a massive Israeli response. The attack was designed to succeed, not to fail. The strike package was modeled on those the Russians have used repeatedly against Ukraine to great effect. The attack caused more limited damage than intended likely because the Iranians underestimated the tremendous advantages Israel has in defending against such strikes compared with Ukraine.

But that isn’t to say that Tehran achieved nothing:

The lessons that Iran will draw from this attack will allow it to build more successful strike packages in the future. The attack probably helped Iran identify the relative strengths and weaknesses of the Israeli air-defense system. Iran will likely also share the lessons it learned in this attack with Russia.

Iran’s ability to penetrate Israeli air defenses with even a small number of large ballistic missiles presents serious security concerns for Israel. The only Iranian missiles that got through hit an Israeli military base, limiting the damage, but a future strike in which several ballistic missiles penetrate Israeli air defenses and hit Tel Aviv or Haifa could cause significant civilian casualties and damage to civilian infrastructure, including ports and energy. . . . Israel and its partners should not emerge from this successful defense with any sense of complacency.