Wikipedia has this wonderful list:
http://en.wikipedia.org/wiki/List_of_invasions
Relevant parts:
2003 invasion of Iraq by United States-led coalition
2001 invasion of Afghanistan by United States-led coalition
1994 invasion of Haiti by a multinational force (MNF) led by the United States
1991 invasion of Kuwait and southern Iraq by a coalition force of 34 nations led by the United States
1989 invasion of Panama by the United States
1983 invasion of Grenada by the United States and allied Caribbean nations
1970 invasion of Cambodia by the United States and South Vietnam
1965 invasion of Dominican Republic by United States and OAS
1962 invasions of South Vietnam by the United States
1961 invasion of Cuba by Cuban allies of the United States, particularly its CIA
<Break for WWII>
1915 invasion of Haiti by the United States
1898 invasion of the Philippines by the United States
1898 invasion of Puerto Rico by the United States
1898 invasion of Spanish Cuba by the United States
1893 invasion of Hawaii by the United States
1871 invasion of Korea by the United States
1861-1865 invasions of the Confederate States by the United States
1846 invasion of Mexico by United States
1813 invasion of Canada by United States
1812 invasions of Canada by United States
1805 invasion of Tripoli by United States and mercenaries
We could debate a few of these but the bigger picture is that you don't get a list like this by accident, especially over a period of only 200 years.