By now you've heard about Harry Reid's embarassing remarks about then-candidate Barack Obama. They were stupid and possibly belie a deep character flaw in Mr. Reid. That said, Republicans should not waste a lot of breath calling for him to resign.
In 2002, Trent Lott resigned his post as Senate Majority leader amid pressure from Democrats and minority groups like the NAACP following flattering remarks Lott made about retiring senator Strom Thurmond's 1948 presidential bid. Thurmond, you may remember if you're 148 years old, wasn't sold on the whole "desegregation" thing back then.
It was wrong to pressure Lott to step down. Lott wasn't any more a racist because of those remarks than Reid is because of his. It was wrong in Lott's case, and it would be wrong in Reid's.
The hypocrisy involved should be mentioned again and again, however. It should be brought up until everyone is sick of hearing about it. Because the next time someone with an (R) after his name makes some insensitive remark, you can bet there will be calls for his head. Racism is a term that has come to mean, "something Republicans say that upsets minorities". That has to change.