US President Donald Trump has given a fairly clear description of what the next phase of the Iran war could look like. The Iranians had tried to rebuild their radar equipment, Trump stated after the most recent wave of US strikes. "We waited until it was almost built, and then we hit it," he said.

On Tuesday, American forces once again attacked several targets in Iran. According to US Central Command (CENTCOM), the targets destroyed included "air defense sites, radar systems, maritime assets and facilities, mine laying capabilities, and communications sites."

'Mowing the grass'

Iran responded by firing rockets and drones at US facilities in the region. With this, the war moved on to what CENTCOM had indicated just a few days earlier could be the strategy for the next phase.

According to the news portal Axios, it was considering limited strikes, at regular intervals if necessary, to prevent Iran from reconstituting its military capabilities in the Strait of Hormuz. An American government representative used a concept from Israeli security policy to describe this idea: He called it "mowing the grass."

The metaphor refers to a strategy that doesn't even attempt to promise that an opponent will be defeated once and for all. It is enough to regularly reduce the enemy's military capabilities to the point where the threat remains manageable. When the grass grows back, you "mow" it again.

Applied to the situation in Iran, this would mean the US keeping an eye on which military capabilities the enemy is reconstituting, and attacking once it crosses a certain threshold.

Successes that won't last

In the past few months, the US has scored some military successes. US forces have significantly reduced Iran's military capabilities in the Strait of Hormuz, and have begun clearing Iranian sea mines.

However, these successes will not last. Tehran is repairing or procuring new radar installations, anti-aircraft positions and anti-ship missiles. US bombs could certainly destroy important Iranian positions with targeted strikes. But the knowledge and the industrial basis of Iranian military technology would remain.

Reconstruction can therefore be delayed, but not prevented. The US will repeatedly be confronted with the same choice: whether to accept that Tehran is regaining its capabilities, or to attack again and destroy them.

Mona Yacoubian, director of the Middle East program at the Center for Strategic and International Studies in Washington, warned as early as April that this development could lead to an "enduring low-intensity conflict punctuated by more intensive interventions."

Trump's belligerent warnings

The fact that the strategy of "mowing the grass" is reaching its limits is also because it was never designed for a war with a state. Israel developed the strategy to combat non-state actors like Hamas.

However, as Yacoubian pointed out in her article, the Israeli academics who initially coined the term warned that if the opponent had "statist characteristics and/or more powerful capabilities, 'mowing the grass' might become an outdated military strategy." This is clearly the case with the Strait of Hormuz.

The US needs to keep the strait reliably open. Iran, on the other hand, only needs to make people believe that the passage remains dangerous. In this way, even a significantly weakened opponent can impose substantial costs on Washington.

Another problem for the US is that, while Washington can determine the intensity of its own attacks, it has no control over Tehran's response. This week, Trump warned Tehran not to launch a retaliatory strike, threatening that Iran would be "totally wiped out as a country" if it did.

Nonetheless, the regime in Tehran immediately fired missiles against American facilities in the region. Jordan alone reported 13 ballistic missiles in its airspace, 10 of which it was able to intercept.

The nuclear question

But Yacoubian believes that repeated American attacks carry a far greater risk. She warns that they may lead Tehran to conclude that "pursuit of a nuclear weapon" is the only way to achieve "lasting deterrence." This suggests that, by attacking Iran, the US and Israel could actually accelerate the precise development they sought to bring under control.

From Washington's perspective, the alternatives available to Trump don't look much better. If the president accepts Iran rebuilding its military strength around the Strait of Hormuz, he risks renewed attacks on shipping and disruption of one of the world's most important energy routes.

The consequences for the global economy are well known. In spite of the upheaval and repeated negotiations, a political agreement between Washington and Tehran has so far failed because of apparently insurmountable differences.

America's next 'forever war'?

For Trump, "mowing the grass" has domestic appeal, in spite of the uncertainty it brings to foreign policy. The US president would be able to avoid occupation, nation building and deploying large numbers of American ground troops.

At the same time, it allows him to distance himself from the so-called "forever wars" he repeatedly accused his predecessors in the White House of pursuing.

Ultimately, though, this supposed way of avoiding a forever war could become one of its own. Yacoubian describes it as a "Sisyphean attrition strategy without end." As long as Washington is not prepared at some point to accept the rebuilding of Iran's capabilities, each successful attack merely creates the justification for the next one.

This article has been translated from German.