Why are Obama's terrorism policies so similar to Bush's?

In this important article in The New Republic, Jack Goldsmith compares President Obama's policies with former President Bush's on 11 terrorism issues: whether we're fighting a "war" or merely fighting "crime," Guantanamo Bay, military detentions, habeas corpus, military commissions, targeted killings, rendition, secret prisons, surveillance, state secrets, and interrogation techniques (including torture). (Goldsmith was an Assistant Attorney General in the Bush administration.)

The whole article is worth reading, but if you want to cut to the chase, here are some of the main points:

Goldsmith's overall assessment:

The Obama administration is still debating many of these issues, and its final policies are not all set. Its changes to Bush practices thus far--cutting back on secret detentions, probable new restrictions on interrogation, and relatively small procedural changes to military commissions--will leave some suspected terrorists in a better place than they would have been under the Bush regime (although Obama's increase in targeted killings will likely result in more deaths and injuries, without due process, to terror suspects and innocent civilians). Even with these caveats, at the end of the day, Obama practices will be much closer to late Bush practices than almost anyone expected in January 2009.

4 rationales for the continuity:

[1.] [T]he late Bush practices were much different than the early ones.... The law was much clearer in 2009 [than in 2001-2003], and there was much greater consensus--across political parties and the branches of government--about permissible policies and their limits. Many Obama policies reflect that consensus.

[2.] [T]he Bush policies were woven into the fabric of the national security architecture in ways that were hard if not impossible to unravel....

So the Obama administration is a bit like a cleaning company that advertises: "We'll make your home look like new!" Then, when they actually come over, they tell you that your main problem is grime that's been around so long it's impossible to remove, and they can only do some light dusting.

Anyway, doesn't point 2 contradict point 1? Bush's policies are so ingrained they're difficult if not impossible to undo -- and by the way, Bush's policies were dramatically overhauled from 2003 to 2009.

Continuing with the rationales:

[3.] [M]any of the Bush policies reflect longstanding executive branch positions. Every wartime president has asserted the right to detain enemy forces without charge or trial during war. Many of them used military commissions for war criminals. Presidents dating back at least to Carter have maintained that habeas corpus review does not extend to aliens detained outside the United States. The state secrets doctrine is over a century old and has been employed vigorously by presidents since the 1970s. Rendition and targeted killings began under Clinton if not earlier. It is no surprise that President Obama seeks to maintain these presidential powers. It would be a surprise if he did not do so....

[4.] President Obama has gone from a legislator and presidential candidate to the commander in chief wholly responsible for the nation's safety. He now reads the same threat reports as President Bush and confronts the same challenge of stopping Islamist terrorists who hide among civilians and who want to use ever-smaller and more deadly weapons to disrupt our way of life. He also faces the same paucity of truly useful information about the enemy and the same hard tradeoffs between liberty and security. And he knows that the American people will blame him and no one else if the terrorists strike.

Goldsmith's rebuke to Dick Cheney:

[T]he former vice president is wrong to say that the new president is dismantling the Bush approach to terrorism. President Obama has not changed much of substance from the late Bush practices, and the changes he has made, including changes in presentation, are designed to fortify the bulk of the Bush program for the long-run. Viewed this way, President Obama is in the process of strengthening the presidency to fight terrorism.

UPDATE: David Brooks points out that the New Republic article debunks both Obama's and Cheney's dueling speeches this week.