Ukraine gained independence in 1991 as the Soviet Union dissolved, declaring itself neutral. A new constitution was adopted in 1996 as the country transitioned to a free market liberal democracy amid endemic corruption and a legacy of state control. The Orange Revolution of 2004–2005 ushered electoral and constitutional reforms. Resurgent political crises prompted a series of mass demonstrations in 2014 known as the Euromaidan, leading to a revolution, at the end of which Russia unilaterally occupied and annexed Ukraine's Crimean Peninsula, and pro-Russian unrest culminated in a war in Donbas with Russian-backed separatists and Russia. Russia launched a full-scale invasion of Ukraine in 2022.