One of the things that most strikes me about the politics of today is that it is the inverse in many ways of the changes that occurred 8 years ago.
In 2001, when Bush took office, many conservatives felt that the office of president had been sullied by Clinton's behavior while holding office. Many of them reiterated for their liberal brethren that Bush is our president now, so sit down and be quiet. Many liberals considered (even at that time) Bush to be akin to the Anti-Christ. To have not voted for Gore was to have been a vote for darkness and chaos.
Now, change the above paragraph, substituting 2009 for 2001, conservative with liberal and vice-versa, Bush for Clinton and McCain for Gore, and you have (aside from the economic and world situation) a virtually perfect inversion.
American liberals and conservatives should keep in mind that they have stood in each others shoes. Remember how you felt when someone denigrated someone you believed in. Remember how fearful you felt. Understand that these feelings are now those of your ideological opposites. This doesn't mean you have to agree, but it should inform how you treat your brothers and sisters. Be kind to each other. We have more in common with each other than we differ.