Victor Davis Hanson is must reading:

In reality, to the extent globalism worked, it followed from three unspoken assumptions:
First, the U.S. economy would keep importing goods from abroad to drive international economic growth.
Second, the U.S. military would keep the sea-lanes open, and trade and travel protected. After the past destruction of fascism and global communism, the Americans, as global sheriff, would continue to deal with the occasional menace like a Moammar Gaddafi, Slobodan Milosevic, Osama bin Laden, Saddam Hussein, Kim Jong-il, or the Taliban.
Third, America would ignore ankle-biting allies and remain engaged with the world — like a good, nurturing mom who at times must put up with the petulance of dependent teenagers.
But there have been a number of indications recently that globalization may soon lose its American parent, who is tiring, both materially and psychologically.