Since being deployed in Israel in 2011, the system, built by the Israeli defence company Rafael in partnership with Raytheon, has proven itself one of the world’s most effective killers of short-range missiles. The Israeli military has said Iron Dome has knocked down about 90 per cent of missiles fired into Israel over the past several years.

As it stands, the US does not have much in the way of excess air and missile defence batteries ready to be transferred. But the Army has been trying to figure out how to operate two Iron Dome systems Congress ordered it to purchase in 2019 as a stopgap for delayed efforts by the service to get its own new air and missile defence systems up and running.

The service bought two batteries that are currently being readied to be put into operation next year. But the Army has struggled to integrate the missile defence: Iron Dome was not designed to operate within the Army’s new command and control system, a problem that limits their usefulness if deployed overseas.

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Enter the House Armed Services Committee.

The HASC’s version of the fiscal 2022 defence bill that was approved on September 2 by a 57-2 margin does not specify any particular weapons system to hand over to the Ukrainians. But one congressional staff member said the language about transferring current systems is telling, and that the Army’s two Iron Dome batteries are prime candidates because there are few relevant systems the Army possesses that could defeat the threat Ukraine faces from Russia.

The Army has long taken the lead on land-based missile defence, but the past two decades of conflict with groups that lack sophisticated missile or drone capabilities led to some underinvestment in short-range air defence weapons. That in turn has made the small number of Patriot and Terminal High Altitude Area Defence batteries some of the Army’s most frequently deployed units in recent years in the Middle East.

Yet the government in Kyiv has suggested in recent months that they’re looking for more. Following the May announcement that Ukraine would begin increasing its annual defence budgets, Ukrainian Defence Minister Andriy Taran said he would like to spend some of it on new air defence systems, pointing to Iron Dome as a possibility.

Those messages were heard in Washington, and members of Congress took note.

“Given the desire and bipartisan recognition that more needs to be done on the integrated air defence front for the Ukrainians, and given some of the administration's policy decisions towards Ukraine recently, there's a desire to try and do more to help them than what the Biden team is doing,” said the staff member, who spoke on condition of anonymity because the bill is still pending on the House floor.

But there are questions about the efficacy of a limited Iron Dome system in Ukraine.

“Tactically it would not be effective at short range, or on the line of contact, because this system would be shot out very quickly by Russian multiple-launch rocket systems,” said Michael Kofman, director of the Russia Studies programme at the CNA think tank. “But it may be able to intercept longer range rockets, which could allow the battery to defend a critical site or command centre” in eastern Ukraine.

The Ukraine air defence amendment was introduced by Florida congressman Scott Franklin and passed by a bipartisan vote.

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The House bill already calls for US$275 million in military aid to Ukraine even before any new transfer of a missile defence system, but any transfer would not add significantly to the total as Iron Dome has already been paid for.

Several Ukrainian and Israeli news reports this spring suggested Kyiv was looking to buy the Iron Dome from Israel, but such a purchase could be complicated. The Israeli government would need Washington’s approval to sell it to a third country given the co-development agreement with US-based Raytheon, and there are sensitivities in Tel Aviv over their relationship with Moscow.

The two countries have agreed to not sell weapons to some third parties such as Ukraine and Iran and have forged an uneasy understanding on Syria in recent years.

Yet there are also downsides to the US Army getting rid of the Iron Dome, even if the service is not able to integrate it into its command and control system.

After two decades of facing few sophisticated missile threats from insurgents in Iraq and Afghanistan, the Army is “facing significant shortages in counter rocket artillery, mortar and cruise missile defence capability,” said Tom Karako, director of the Centre for Strategic and International Security’s Missile Defence Project. “And the reason they adopted Iron Dome with the encouragement of Congress – was really a reflection of that capability gap.”

One Army official who spoke on background to discuss the sensitive issue said that while Iron Dome cannot work with other systems the service is fielding, plenty of other current weapons and sensors cannot “talk” to one another either. But that was a problem the Army did not want to compound by buying more gear that would only make the issue worse.

The amendment that features the Ukraine missile defence language is nestled within HASC senior member Mike Rogers’ US$24 billion funding increase to the Biden defence policy bill. The package also includes a US$25 million increase to the US$250 million Ukraine Security Assistance Initiative, bringing it back up to the 2021 level of US$275 million.

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In June, POLITICO reported that the Biden administration had put together a new US$100 million military aid package to Ukraine, only to put the plan on hold after Russian troops moved away from the Ukraine border this spring after a series of exercises. The package included short-range air defence systems, small arms and anti-tank weapons, marking a departure from the non-lethal weapons the Biden administration provided this year under two separate packages, one announced in March and a second in June.

It is not clear what the eventual fate of the Ukraine funding increases will be once the bill heads to the full House and then is taken up by House and Senate conference committees later this year to hash out a final bill.

In July, the Senate Armed Services Committee approved a US$25 billion increase to the defence budget by a 25-1 margin, suggesting both houses of Congress agree broadly that the president’s US$715 billion Pentagon spending plan did not make the grade.

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