This is from Claude: "Gorbachev (1990): Declassified U.S., Soviet, German, French, and British documents show Secretary of State James Baker assured Gorbachev that if a united Germany stayed in NATO, there would be no extension of NATO's jurisdiction eastward. This wasn't just Baker — multiple Western leaders, including Bush, Kohl, Genscher, Thatcher, and Mitterrand, all conveyed similar assurances to Soviet leaders in 1990. Crucially, these assurances were never written into a formal treaty, though the record shows a clear pattern of communication from top Western officials creating a real expectation on the Soviet side."