Short answers, pulled from the story.
The Jackson-Vanik amendment is a 1974 provision of the Trade Act of 1974 that denied normal trade relations to nonmarket economies, originally the countries of the Soviet Bloc, that restricted freedom of emigration. Congress passed the underlying trade bill unanimously, and President Gerald Ford signed it into law on the 3rd of January 1975.
Henry M. Jackson, a Democratic senator from Washington, drafted the amendment in 1972 and introduced it to Congress on the 4th of October 1972. Charles A. Vanik, a Democratic representative from Ohio, introduced the House version in 1973, and the amendment is named for both men.
The Jackson-Vanik amendment's application to Russia was repealed on the 14th of December 2012, when President Barack Obama signed a law also known as the Magnitsky Act. The same law granted Russia and Moldova normal trade relations and shifted the focus toward punishing individual human rights violators.
Congress passed the Jackson-Vanik amendment to pressure the Soviet Union and other nonmarket economies into allowing freedom of emigration, especially for Jewish citizens facing a 1972 Soviet head tax on educated emigrants. Senator Henry Jackson believed the right to emigrate was one of the most powerful human rights, since it forced governments to improve conditions or lose their citizens.
The Jackson-Vanik amendment covered the Soviet Union and later the post-Soviet states, the People's Republic of China, Romania, Hungary, Czechoslovakia, East Germany, Bulgaria, Mongolia, Albania, Cambodia, Laos, and Vietnam. Poland and Yugoslavia were exempt outright, though Poland's status was suspended in 1982-1987 and Serbia and Montenegro's status was suspended in 1991-1992.
Since 1975, more than 500,000 refugees, including many Jews, evangelical Christians, and Catholics from the former Soviet Union, have resettled in the United States. An estimated one million Soviet Jews also immigrated to Israel over the same period.