Gotta disagree - American armed intervention, be it through state-sponsored assassinations (such as in the DRC, executing the democratically elected Patrice Lumumba) or through the numerous invasions during the Cold War (Korea, Vietnam, Grenada, etc) or through sponsored coup d'etats against democratically elected leaders (Guatemala, Chilé, Venezuela recently) has always been a central part of America's foreign policy. They care not for your politics, only that you support American interests, be they business or politics.
Exaggerate much? Of those incidents listed, only Grenada counts as an invasion. Both Korea and Vietnam were wars fought for the purpose of assisting allies. As for the claims of sponsored coup d'etats... you would have had a better chance arguing Iran, the DR, Cuba etc... which, in any event was already covered by my preface that "there have been times in American history..."
At any rate I don't think you appreciate what "ruling by the gun" means.
What do you mean by ruling by the gun? To me it represents compliance through state-backed violence.
American invasions/armed conflicts since WWII;
1947 - troops land to reinstate Greek monarchy in Greece
1950 - US puts down revolt in Puerto Rico
1950 - Korean War (it was to stop communism, not 'assisting allies' per se, who were cut-throat dictatorial ass-hats)
1950 - fleet prevents Chinese attacks on Taiwan (thus protecting the Western-backed losers of the Chinese civil war, the ROC)
1955 - military advisors land in Vietnam
1959 - Vietnam (again propping up ass-hat dictators to prevent spread of communism)
1962 - Marine Expeditionary forces land in Thailand to prevent communism spreading
1962 - Kennedy quarantines Cuba, Cuban missile crisis
1962 - America starts supporting/(bombing in 1968) Laos
1965 - America invades Dominican Republic, crushing popular uprising to reinstate democratically elected leader and placing CIA-favoured leader in his place
1970 - Cambodia (more anti-communism attacks)
1973 - America supports Israel during Yom Kippur War
1981 - "military training" in El Salvador
1983 - America invades Grenada
1986 - America strikes Libya in response to his supporting terrorist bombings
1987 - America retaliates by attacking Iranian oil platforms for an attack on an oil tanker (bunch of retaliations around this period)
1988 - Troops sent to Honduras after (socialist) Nicaragua threatens them
1988-90 - America deposes Manuel Noriega from Head of State of Panama, having been on the CIA payroll a decade earlier (who helped him rise to the position in the first place)
1989 - America helps defeat a coup attempt in the Philippines, for once preserving democracy
1990-1991 - Operation Desert Storm (First Gulf War)
1992-2003 - US/UK enforce no-fly zones over Iraq
1992-1995 - US troops sent to Somalia
1993-1995 - US enforces no-fly zone over Bosnia
1994-1995 - US troops restore democratically-elected Haitian President 3 years after coup
1995 - America bombs Bosnian Serb army
1996 - America protects Kurds in Kuwait
1998 - US/UK bomb Iraq
1999 - US/NATO bomb Serbia and Serb positions in Kosovo
2001 - Invasion of Afghanistan
2001 - "War on Terror" involves increased military presence in the Middle East, especially Yemen
2003 - Invasion of Iraq
2004 - Drone attacks in Pakistan start
2004 - US increases presence in Georgia, Djibouti, Kenya, Ethiopia, Yemen and Eritrea
2011 - US bombs Libya during civil war
Non-military 'rule by gun' - There's a truck load more but I got bored writing it all down
1950s - Due to threats to US control of Chilean resources, CIA character-assassinates and impedes leftist candidates in Presidential elections
1952 - First attempt by CIA to overthrow Guatemalan (democratically elected, but left-leaning) president in a coup d'etat
1953 - CIA sends death threats to leading communists in Guatemala
1954 - CIA overthrows Guatemalan President in coup d'état, installing a military junta
1958 - US supported Chilean government lowers tariffs, destroying domestic markets which are flooded with American products. US govenment increases funding ($130 mil) to prevent policy change. They interfere with Chilean elections for the next 7 years
1961 - CIA helps assassinate President of Dominican Republic
1964 - CIA sets up in Bolivia, helps launch coup d'état, gives $1,000,000 dollars (about $6.7 million today) to election campaign and aids in brutal suppression of opposition over the next 5 years
1964 - Aids coup d'état in Brazil, replaces democratically elected president with military dictatorship due to non-support of Bay of Pigs. Also character-assassinates president due to threat of nationalising the phone company of Brazil (who's CEO was friends with director of CIA)
1965 - President Johnson tries to justify invasion of Guatemala, fails
1966 - CIA takes steps to prevent Cheddi Jagan from winning election in Guyana (he finally wins, in 1992....)
1967 - CIA helps capture and kill Che Guevara
1970 - Leftist wins Chilean election, US Government funds everything possible to overthrow and discredit Allende, from bribing officials, supporting guerillas, cutting all aid, funding media, bribing labour unions and eventually a coup
1973 - Chilean coup, supported by CIA, brings Pinochet to power. US supports military regime while it brutalises and murders its own citizens. CIA even has a part in the death of 4 American citizens.
1980s - CIA helps fight opposition to dictatorial government, thwarts coup in 1983
1981 - Nixon sets CIA up in Nicaragua to fund the Contras, started disrupting government by blowing up bridges and other infrastructure, in order to undermine Saninistas (who were perceived to be communists, even Congress didn't think they were communists)
1983 - CIA starts assassinating Nicaraguan officials as part of psychological warfare, also dabbles in drug-trading
1984 - CIA sets up in Honduras, trains torturers
1984 - Congress prevents funding of Contras in Nicaragua, International Court of Justice demands US pay reparations, US refuses
1987 - CIA helps interrogate and torture "suspected leftists" in Honduras
1993 - CIA helps overthrow Elías, president of Guatemala (who had suspended the constitution and attempted a self-coup)
1995 - America/CIA implicated in Human Rights report on Honduras kidnapping, torture, and attempted murder of 6 student activists
here's a wiki page for wars involving US -
http://en.wikipedia.org/wiki/List_of_wars_involving_the_United_StatesCIA wiki page has a box at the bottom, if you "show" the CIA box, you an see activities by geographical locale. There's a lot to get through