Americans have an unsual way of identifying themselves ethnically. Throughout much of the country people, especially the South, people genetically descended from Northwest Europeans simply refer to their ethnicity as "Americans" with no further qualification. All other people in America generally hyphenate a particular race, ethnicity or religion to give distiction follow by "-American". How every American choses to identify himself on the U.S. Census is in iteself a very interesting and much studied topic.
If you ask a 'non-ethic' white in the tire shop or barber shop what his race or heritage is, he will tell you he is "White"
"White Americans" through much of the country, and particularly the South, use the term "White" in several ways that can easily be misunderstood.
Although "White" can be substituted for Caucausian, many Whites use the term as an ethnic distinction. For example, it may refer exclusively to native born American Whites who are generally descended from the British Islands with minor inputs from Germans, France, etc.
White can also mean a Northern European type people to the exclusion of what are sometimes called "ethnics' or "ethnic whites" (in other words, people from another European culture, religion or culture)
American "Whites" generally seem to identify somewhat with their assumed to be native culture (like being Irish, German or Scottish) but strangely almost never identify with England. That is bizarre given the genealogical data white suggests that American Whites and a component of all other ethnicities (such as Cherokees or Blacks) have very substantial amounts of English ancestry.