What is the worse thing President Obama has done?
A few things to compare your answers to:
The Conservative/ Republican standard bearer Ronald Reagan signed the bill into law that granted amnesty to millions of illegal immigrants. (The Immigration Reform and Control Act 1986) When President Reagan signed the bill, he declared, "It will remove the incentive for illegal immigration." Boy was he wrong!
Reagan signed the largest peacetime tax increase in American history into law. (Tax Equity and Fiscal Responsibility Act of 1982)
George Bush started a war based on information that even he admits turned out to be false.
In 2007 Bush remove North Korea from the list of state sponsors of terrorism and gave them 900,000 tons of heavy-fuel oil to stop their nuclear program. As you can see that did not work.
Bush filmed a joke about searching for weapons of mass destruction while he had men in the field dying and being injured while searching for weapons of mass destruction.