Families of four soldiers, including two from Staffordshire, killed in Iraq must wait to hear whether a High Court judge will allow them to seek compensation from the Government.
Relatives say the Ministry of Defence (MoD) failed to provide armoured vehicles or equipment which could have saved lives.
But MoD lawyers say decisions about battlefield equipment are for politicians and military commanders and have asked a judge to stop compensation claims going forward.
Mr Justice Owen reserved judgment after hearing arguments from all sides during a three-day hearing at the High Court in London.
Lawyers say he is unlikely to rule for at least a month.
The judge heard that compensation claims had been made following an incident in which a British Challenger tank opened fire on another British Challenger tank, after an officer became "disorientated", and incidents in which soldiers died after Snatch Land Rovers hit improvised bombs.
Private Phillip Hewett, 21, of Tamworth, died in July 2005 after a Snatch Land Rover was blown up. Similar explosions claimed the lives of Private Lee Ellis, 23, of Wythenshawe, Greater Manchester, in February 2006 and Lance Corporal Kirk Redpath, 22, of Romford, Essex, in August 2007.
Corporal Stephen Allbutt, 35, of Sneyd Green, Stoke-on-Trent, Staffordshire, was killed by "friendly fire" in March 2003 after his Challenger 2 tank was hit by another Challenger 2 tank.
Their families are arguing that the MoD should have ensured that tanks were "properly equipped" with technology or equipment which would "on the balance of probabilities" have prevented the "friendly fire" incident and also ensured that "vehicle recognition training" was in place for troops.
Relatives also claim that the MoD put soldiers at "unnecessary and unreasonable risk" by providing "poorly armoured" Snatch Land Rovers when better-armoured vehicles - such as the Cougar, used by American troops, were available.
James Eadie QC, for the MoD, asked the judge to "strike out" the claims. "Should the court decide this issue? My submission is plainly not," he told the court. "They are political decisions, not legal decisions."