But Future Combat Systems is “by far the biggest single investment the US Army is planning to make during the next 20 years,” the Congressional Budget Office said. The programme will take up about half of the Army’s procurement budget in 2015 and stay at about that level over the next decade, leaving little money for other weapons.

“The Army has some huge long-term budget problems,” said Steven M. Kosiak, vice president of budget studies at the Centre for Strategic and Budgetary Assessments, a defence think tank. The question isn’t so much how the government will pay for the conflicts in Iraq and Afghanistan now, he said. That’s being covered by supplemental budgets. The issue is how the Army will afford Future Combat Systems at the same time it’s grappling with the cost of adding 65,000 troops and covering rising health care and compensation expenses. “Can you really afford to equip and upgrade the rest of the Army?” Kosiak said.

But Brig. Gen. James Terry, who oversees doctrine and training for Future Combat Systems at Fort Bliss, said, “We have to head toward the future,” he said, adding, “I think the train left the station a couple of years ago.”