When I have a word like "U.S." in a sentence, I'm using code like this:

     After the U.S.\ Army left Vietnam, they focused on...

...that seems to make sure the space between U.S. Army isn't so big.

My copy editor noticed that when I use footnote, there isn't the right space after, like.

     Here is a sentence.\footnote{This is footnote text.} This is another sentence.

They are saying that after that, the space isn't the right size. Is there something similar to the first option that makes sure a full end-of-sentence space width appears?

--Joel