I hardly have the energy to wrestle with George W. Bush's public statements on grand strategy anymore, but when he says something like "If we were to fail, they'd come and get us" it's worth asking what, exactly, the causal chain here is supposed to be. US troops in Iraq aren't trying to prevent people currently in Iraq from leaving Iraq. And while various government agencies are trying to stop terrorists people from entering the United States, American troops in Iraq aren't doing this.
The US is particularly miserable at putting aside money for the future. Should we blame our paychecks or our psychology?