Dick Cheney, the hard-driving former U.S. vice president who wielded unparalleled influence during the George W. Bush administration and became one of the most consequential and controversial figures in modern American politics, has died at 84.

No cause of death was immediately released but, Cheney, who served as vice president from 2001 to 2009, was a key architect of the U.S. response to the September 11 attacks, including the wars in Afghanistan and Iraq.

His advocacy for expanded executive power and use of harsh interrogation tactics made him a lightning rod for criticism but also a symbol of unflinching national defense for his supporters.

Before becoming vice president, Cheney held a long career in public service, including as defense secretary under President George H. W. Bush during the 1991 Gulf War and as a congressman from Wyoming.