1993 President Clinton meets with Russian President Yeltsin in Vancouver, above; they vow to cooperate “to promote democracy, security, and peace.” (Photo: Alamy)

1993 A memo prepared for Secretary Warren Christopher provides a timetable for NATO expansion, with Russia and Ukraine in line to be admitted in 2005.

1997 Clinton and Yeltsin sign the NATO-Russia Founding Act, affirming that NATO and Russia are not adversaries.

1999 Poland, Hungary and the Czech Republic become the first former Soviet bloc states to join NATO, expanding the alliance’s borders 400 miles toward Russia.

2004 November Seven countries, including three former Soviet Baltic republics, Estonia, Latvia, and Lithuania, join NATO.

2007 In an address at a security conference summit in Munich, Russia’s president, Vladimir Putin, sharply criticizes the United States, saying it had “overstepped its national borders, and in every area.”

2008 April At the NATO summit in Bucharest, the council issues a declaration stating that Ukraine and Georgia would be admitted to the alliance.

2008 Russia goes into war with Georgia and takes control of its two Russian-backed separatist regions.

2014 Russia annexes the Crimean Peninsula from Ukraine, violating international law. The U.S. responds by imposing sanctions, costing the Russian economy about $50 billion annually, according to the Atlantic Council, yet were unsuccessful in reversing the invasion.

2021 Russia amasses more than 100,000 troops near its border with Ukraine, a move that aligns with Putin’s long-term strategic interests in the region.

2022 Russia launches a full-scale invasion of Ukraine on Feb. 24.

IREM OZTURAN, an intern at Retro Report, is a journalism and economics student at Northwestern University. This article first appeared in Retro Report’s free weekly newsletter. Subscribe and receive lessons from history in your mailbox. Follow us on Twitter @RetroReport.

FOR CONTEXT Several times during the Cold War, the United States and the Soviet Union came close to a nuclear confrontation. Faced with the risk of mutual destruction, the two sides began to reduce their nuclear arsenals. More countries are obtaining nuclear weapons today.