On his second day in office, Obama issued executive orders that did just that, bringing about the most sweeping changes to the nation's security policy since the aftermath of the Sept. 11 attacks.
Obama's orders would close the detention center at Guantanamo Bay, Cuba, within one year; establish a task force to review the cases of the more than 200 detainees held there and close CIA interrogation facilities around the world.
That pledge to end harsh interrogation practices continues to cause headaches for the Obama White House as the issue has shifted to what should be done, if anything, to former Bush officials who developed the policies that allowed these techniques.
As a candidate, Obama said his top priority at the start of his administration would be to assemble the joint chiefs of staff and give them new marching orders on developing a withdrawal plan for Iraq.
On his first full day as president, Obama met with the military commanders in charge of Iraq to talk about a plan to end the war. On Feb. 27, Obama announced an 18-month drawdown plan that would end the mission in Iraq on Aug. 31, 2010, but keep 35,000 to 50,000 troops there.
This does not quite fulfill Obama's campaign promise to withdraw all American combat troops within 16 months of taking office.
On March 27, Obama announced his plan to send 4,000 more U.S. troops to Afghanistan and add civilian aid to improve development efforts there and in Pakistan as well.
Obama said that for six years, Afghanistan has been "denied the resources that it demands" because of the focus on the war in Iraq.
Obama wasted no time getting down to business on his pledge to institute tougher policies on ethics and transparency issues for the federal government, signing two executive orders and three presidential memoranda Jan. 21.
With his signature, Obama put in place new rules on openness and transparency for his administration and futures ones, including efforts to shut the revolving door between the lobbying world and the federal government.
Under Obama's rules, lobbyists who become members of the administration will not be able to work on matters they lobbied on for two years, or in the agencies they lobbied during the previous two years.
After a staffer leaves the Obama administration, they cannot lobby the administration. The president also instituted a ban on gifts from lobbyists to members of the administration.
There were exceptions to the lobbying rule, however, most notably Deputy Defense Secretary William Lynn, who was a registered lobbyist before being appointed to his Pentagon post. The White House said he was granted a waiver that would allow him to serve and still meet the president's standards.
During the campaign, Obama said he would convene a health care summit and put all the deliberations out in the open.
"I'm going to have all the negotiations around a big table. We'll have doctors and nurses and hospital administrators. Insurance companies, drug companies -- they'll get a seat at the table, they just won't be able to buy every chair," he said Oct. 26, 2008. "But what we'll do is we'll have the negotiations televised on C-SPAN, so that people can see who is making arguments on behalf of their constituents and who are making arguments on behalf of drug companies or the insurance companies."