Don't worry Sarah Palin, I don't really understand the Bush Doctrine either. And neither do people who actually work/worked for President Bush.
Many Versions of 'Bush Doctrine' (Washington Post)
One of my favorite quotes from the piece comes from Philip Zelikow, who worked for the White House and the State Department under the president:
"I actually never thought there was a Bush doctrine...Indeed, I believe the assertion that there is such a doctrine lends greater coherence to the administration's policies than they deserve."