To lobby in American politics means to talk to legislators in private to convince them to vote a certain way on specific legislation. As a noun, a "lobby" is an organization that lobbies legislatures, either for pay from a sponsor or as a public service. A lobby works for an interest group.
In recent decades thousands of lobbyists are at work in Washington D.C. for every possible interest. Lobbyists are also active in all the state capitols. Many lobbyists are former members of Congress or former staffers.
Since 1900 lobbying has became a legal, regulated institution in America. In 1946 for example, Congress required the registration of lobbyists. Key to the process leading up to lobbying's institutionalization and regulation were the congressional investigations of lobbyists in 1913, 1927-28, 1935-38, and the 1950s, which revealed the methods lobbyists used. This information has helped shape legislation aimed at reducing corruption and lending transparency to the legislative process. Since 1990, American states have adopted a variety of reforms to regulate lobbying in an attempt to address a host of ethical issues.
In the 19th century, the most important lobbies worked on behalf of a wool tariff and railroad subsidies in the 1865-900 era. In the South during Reconstruction lobbyists were very active in state capitols, seeking and getting subsidies for railroads. Many times they had to bribe legislators. In the early 20th century effective lobbyists represented the Anti-Saloon League (to prohibit alcohol, and farm interests.
Lobbying was in bad odor in the Progressive Era early 20th century, with many reformers (like Woodrow Wilson) convinced that it undermined representative government by skewing the thinking of legislators. Thanks to the new field of psychology, lobbyists began to employ propaganda techniques during the early 20th century to assert a more prominent role in the policy making process in the U.S. It is noted that while lobbyists amplified their constituents' power and influence, the methods they employed using false and misleading information cast doubt on the ability of ordinary citizens to participate in democratic politics.
In reality, lobbyists spend most of their efforts providing information on specific legislation, pro or con (such as the conservative NRA's Second Amendment gun rights versus the liberal Mayors Against Illegal Guns's gun control), and letting the "information" sway the legislator. Often they testify before committees in open hearings. On controversial issues there may be two or more) teams of opposing lobbyists.
Corporate LobbiesFour years ago, the United States Supreme Court suggested that corporate spending to influence federal elections would not “give rise to corruption or the appearance of corruption,” the majority wrote in the landmark Citizens United v. Federal Election Commission decision. According to recent analysis by the Sunlight Foundation 
"Between 2007 and 2012, 200 of America’s most politically active corporations spent a combined $5.8 billion (with a B) on federal lobbying and campaign contributions. What they gave pales compared to what those same corporations got: $4.4 trillion (with a T) in federal business and support. Putting that in context, the $4.4 trillion total represents two-thirds of the $6.5 trillion that individual taxpayers paid into the federal treasury. Said otherwise, by spending: a paltry $6 billion to bribe the US government, or just a little more than what GM will spend on stock buybacks alone, US corporations are getting the direct benefit of two-thirds of US taxpayers' labor! And here is the visual representation of this stunning finding: for every dollar spent on influencing politics, the nation’s most politically active corporations received $760 from the government. Which translates into an Internal Rate Of Return of, hold on to your hats folks, 75,900%!"
Before the Civil War, the Christian lobby called for the abolition of slavery. It was politically weak and the target of ridicule before the Civil War, when it suddenly became powerful and won its case. Many continued to lobby on behalf of the Freedmen during Reconstruction. After 1870 Protestant lobbyists formed working partnerships with Southern Democrats (who had a base of Protestant support), along with many Republicans who represented pietistic Protestant districts in the North. The lobbyists (and the groups they represented), pushed through Congress effective federal policies against polygamy, laws banning obscenity and prizefight films from interstate commerce and the mails, and (especially in the states) laws to restrict prostitution, sex with underage girls, and easy divorce. They tried not only to put God in the Constitution]] but also, through persuasion and legislation, to control drinking, obesity, divorce, Sabbath observance, gambling, smoking, prize fighting, prostitution, and sex with underage girls. Most significantly, they fought for prohibition -- and under professional leadership of the Anti-Saloon League, finally won. Famous leaders included Frances Willard of the Woman's Christian Temperance Union, Wayne Wheeler of the Anti-Saloon League, and anti-pornography campaigner Anthony Comstock, whose laws against obscenity remain the law of the land. Proposed constitutional amendments regulating divorce and declaring the United States a Christian nation never reached the floor of Congress. Neither did the proposal for federal censorship of movies.
Right to Vote
The woman suffragists tried lobbying as well, but found their best success when they appealed to male voters at election time.
Second Amendment Unalienable Rights
The National Rifle Association, the Second Amendment Foundation, the Gun Owners of America and the Jews for the Preservation of Firearms Ownership lobby to protect and defend the Second Amendment right to self-defense.
ScandalsBribery has always been illegal and hints of bribery destroy the effectiveness of a lobbyist -- and seriously hurt major politicians such as James G. Blaine.
- Balogh, Brian “‘Mirrors of Desires’: Interest Groups, Elections, and the Targeted Style in Twentieth-Century America,” in Meg Jacobs, William J. Novak, and Julian Zelizer, eds. The Democratic Experiment: New Directions in American Political Theory, (2003), 222–49
- Baumgartner, Frank R., and Beth L. Leech. Basic Interests: The Importance of Groups in Politics and in Political Science (1998), 64–82, reviews the political science literature
- Browne, William Paul. Groups, Interests, and U.S. Public Policy (1998) online edition
- Clemens, Elisabeth S. The People’s Lobby: Organizational Innovation and the Rise of Interest-Group Politics in the United States, 1890–1925 (1997)
- Foster, Gaines M. Moral Reconstruction: Christian Lobbyists and the Federal Legislation of Morality, 1865-1920 (2002) online edition
- Hansen, John M. Gaining Access: Congress and the Farm Lobby, 1919–1981 (1991);
- Loomis, Christopher M. "The Politics of Uncertainty: Lobbyists and Propaganda in Early Twentieth-Century America," Journal of Policy History Volume 21, Number 2, 2009 in Project MUSE
- Thompson, Margaret S. The "Spider Web": Congress and Lobbying in the Age of Grant (1985) on 1870s
- Tichenor, Daniel J. and Richard A. Harris, “Organized Interests and American Political Development,” Political Science Quarterly 117 (Winter 2002–3): 587–612 online
- Durden, Tyler, "[http://www.zerohedge.com/news/2015-03-16/words-greatest-investment-every-dollar-spent-influencing-us-politics-corporations-ge The Best "Democracy" Money Can Buy: For Every Dollar Spent Influencing US Politics, Corporations Get $760 Back", Zero Hedge, Published March 16, 2015.
- Loomis (2009)
- Thomas T. Holyoke, "Interest Group Competition and Cooperation at Legislative Hearings," Congress & the Presidency 2008 35(2): 17-38,
- Allison, Bill and Harkins, Sarah, Fixed Fortunes: Biggest corporate political interests spend billions, get trillions, Published November 17, 2014. Accessed March 20, 2015.
- Durden, Tyler, "[http://www.zerohedge.com/news/2015-03-16/words-greatest-investment-every-dollar-spent-influencing-us-politics-corporations-ge The Best "Democracy" Money Can Buy: For Every Dollar Spent Influencing US Politics, Corporations Get $760 Back", Zero Hedge, Published March 16, 2015. Accessed March 20, 2015.
- "Pietism, German Pietismus, influential religious reform movement that began among German Lutherans in the 17th century. It emphasized personal faith against the main Lutheran church’s perceived stress on doctrine and theology over Christian living. Pietism quickly spread and later became concerned with social and educational matters. As a phenomenon of personal religious renewal, its indirect influence has persisted in Germany and other parts of Europe into the 21st century." Fair use Pietism, Encyclopedia Britannica, Chicago, Illinois, http://www.britannica.com/EBchecked/topic/459967/Pietism
- Foster (2002)
- David Howard Goldberg, Foreign Policy and Ethnic Interest Groups: American and Canadian Jews Lobby for Israel (1990) online edition