The U.S. Army's M1 Abrams first entered service in the 1980s, and with its dated M-60 Patton tanks overwhelmingly outmatched by their Soviet counterparts such as the T-72 the new battle tank provided a much needed boost to American armoured warfare capabilities. The battle tank today remains likely the most advanced and capable Western platform in service. While the German Leopard 2 had previously contested this title the tank's gross underperformance in both Iraq and Syria during its first major combat tests revealed it to be something of a paper tiger when considering its reputation as a near invulnerable platform. The M1 Abrams is today relied on to engage the most advanced armoured units of potential adversaries, from the Chinese Type 99 to the Russian T-90M2 and T-14 Armata, and its importance to the armoured warfare capabilities of the United States and by extension the entire Western bloc cannot be overstated.While exports of the M1 Abrams have been relatively limited, in the aftermath of the U.S. invasion of Iraq the Iraqi army was rebuilt as an American armed force and needed a reliable platform to replace the Soviet T-72. The country was thus provided with the elite U.S. battle tanks in large numbers. With the near collapse of the Iraqi military following the rise of the Islamic State in 2014, Iraq's government was forces to rely on closer cooperation with Shiite militias to restore order and combat IS forces. Forces such as Hezbollah in Iraq maintained close ties to and were supplied by Iran, and these militias have since reportedly acquired M1 Abrams tanks - though whether these were abandoned by government forces or covertly provided remains uncertain. According to a report by the U.S. State Department. "The U.S. Department of&nbsp;State acknowledged that some U.S. provided military equipment sent to&nbsp;support the mission, including as&nbsp;many as&nbsp;nine M1 Abrams tanks, had fallen into&nbsp;the hands of&nbsp;Iranian-backed militias that fought against Islamic State in&nbsp;Iraq."&nbsp;Shite militias are very often advised in the field by Iranian officers, and can function as extensions of Iranian power in Iraq. Their acquisition of the Abrams could as a result have severe implications.&nbsp;While this is hardly the first time U.S. Arms change hands during the Iraqi conflict, the Islamic State's large fleet of U.S. made Humvees and Black Hawk helicopters being another example, the acquisition of the M1 by Iranian backed forces remains perhaps the most detrimental incident yet to U.S. interests. It remains highly likely that the Abrams will be sent to Iran for study, with the country having built its own battle tanks, the Karrar, based on reverse engineered British and Russian technologies which could be developed further through a study of the U.S. platform. Iran in turn has a long history of sharing intelligence on and delivering samples of Western arms to North Korea, Russia and China - the other three powers named by the United States as its 'great power adversaries.' The RQ-170 Stealth Drone, F-14 Tomcat Heavy Fighter and AIM-54 Phoenix Missile were some of the most prolific examples of advanced U.S. military technologies Iran both reverse engineered as well as provided to U.S. adversaries. While Russia and China are notably both ahead of the U.S. in their armoured warfare technological capabilities, the three powers could study the Abrams to exploit weaknesses in a potential ground war with the U.S. - and possibly reverse engineer some of its technologies for their own tank designs. While Iraq was only provided with export variants of the M1, which lacked several advanced features of the platforms operated by the U.S. military itself, the opportunity to study the battle tank will nevertheless be a valuable asset to the United States' potential adversaries.