According to many, did the US pull out the troops tomorrow, there would be no blood bath at all ( at least, nothing worse than it is now ). Vietnam is an example.
Vietnam after the US pulled out was hardly a paradise on earth. One source:
" Vietnam, post-war Communist regime (1975 et seq.): 430 000
* Jacqueline Desbarats and Karl Jackson ("Vietnam 1975-1982: The Cruel Peace", in The Washington Quarterly, Fall 1985) estimated that there had been around 65,000 executions. This number is repeated in the Sept. 1985 Dept. of State Bulletin article on Vietnam.
* Orange County Register (29 April 2001): 1 million sent to camps and 165,000 died.
* Northwest Asian Weekly (5 July 1996): 150,000-175,000 camp prisoners unaccounted for.
* Estimates for the number of Boat People who died:
o Elizabeth Becker (When the War Was Over, 1986) cites the UN High Commissioner on Refugees: 250,000 boat people died at sea; 929,600 reached asylum
o The 20 July 1986 San Diego Union-Tribune cites the UN Refugee Commission: 200,000 to 250,000 boat people had died at sea since 1975.
o The 3 Aug. 1979 Washington Post cites the Australian immigration minister's estimate that 200,000 refugees had died at sea since 1975.
+ Also: "Some estimates have said that around half of those who set out do not survive."
o The 1991 Information Please Almanac cites unspecified "US Officials" that 100,000 boat people died fleeing Vietnam.
o Hanson, Victor Davis, Carnage and culture (2001): 50,000-100,000
o Encarta estimates that 0.5M fled, and 10-15% died, for a death toll of 50-75,000.
o Nayan Chanda, Brother Enemy (1986): ¼M Chinese refugees in two years, 30,000 to 40,000 of whom died at sea. (These numbers also repeated by Marilyn Young, The Vietnam Wars: 1945-1990 (1991))
* Rummel
o Vietnamese democide: 1,040,000 (1975-87)
+ Executions: 100,000
+ Camp Deaths: 95,000
+ Forced Labor: 48,000
+ Democides in Cambodia: 460,000
+ Democides in Laos: 87,000
+ Boat People: 500,000 deaths (50% not blamed on the Vietnamese govt.)
* ANALYSIS: I'd say the most likely total would be 430,000. That's 65,000 executions + 165,000 camp deaths + 200,000 boat people. It's unlikely that VN alone caused 460+87T democides in Cambodia + Laos since estimates of the total deaths in these conflicts only run to a half million or so."
http://users.erols.com/mwhite28/warstat3.htm