By Jonathan Beale
BBC News, Washington
So far there has been little controversy from the changes
Barack Obama's election mantra was "Change!" - and he is trying to live up to the campaign promise.
The new president has already made his mark within just a few months of entering the White House.
With a stroke of a pen he has already erased or reversed some of the Bush administration's most controversial policies.
Policy switches have so far included:
- his promise to close down Guantanamo
- the decision to end harsh interrogation techniques on terrorist suspects
- and the order enabling states like California to regulate vehicle emissions.
With the focus on the state of the economy some of these U-turns may have escaped your attention.
And so far there has been little controversy. But that may change as Barack Obama wades into some of the issues that can reignite America's "culture wars".
Take the president's decision to reverse the Mexico City Rule - it blocked federal funding for charities abroad that promoted or carried out abortions.
OBAMA POLICY CHANGES
Since entering the White House, Barack Obama has:
Ordered the closure of the Guantanamo Bay prison camp
Outlawed CIA use of harsh interrogation techniques
Enabled states to set tougher car emissions standards
Reversed the ban on federal funding for aid agencies that perform abortions
Removed "conscience" protections for health workers who refuse to issue contraception
Hardly a political earthquake - but it did not go down well with Christian conservatives.
And now the president's most recent announcement - to reverse the Bush administration's ban on federal funding for new embryonic stem cell research.
Again, it is not the number one issue on most people's minds - but it may further alienate cultural and social conservatives who believe that embryos are human life and should not be destroyed.
That said, there are plenty of reasons why Barack Obama has ventured into these choppy waters.
The most obvious is to prove that he is different from President Bush.
Remember, "W" was perceived as "anti-science", as a man who disputed the claims of man-made climate change. He was viewed as a sceptic not just of science but of intellectual curiosity itself. Barack Obama is happy to be seen as the opposite.
Mr Obama also clearly believes that American scientists and science have been left at a disadvantage by the Bush ban on embryonic stem cell research.
As he tries to kick-start the US economy he needs to encourage development in all scientific fields. Government grants in this area could create American jobs.
'Person of faith'
More importantly, he fears that medical progress has been impeded by the ban.
Mr Obama repeated the claims of some scientists that embryonic stem cell research could lead to a cure for a whole host of diseases like Parkinson's, Alzheimer's and diabetes and that it could even help someone who is paralysed to walk again.
But he was careful not to overstate the case: "The full promise of stem cell research remains unknown, and it should not be overstated" he said.
Barack Obama is clearly at odds with many conservatives, who oppose stem cell research on ethical grounds.
But what is most striking about this decision is his attempt not to alienate conservatives or to sidestep the moral debate.
"Many thoughtful and decent people are conflicted about, or strongly oppose this research," he acknowledged.
His description of himself as "a person of faith" made it harder for his critics to attack his decision.
Embryonic stem cell research, he argued, is the right, moral thing to do because it aims to relieve "human suffering". He promised strict guidelines and controls on new research.
Mr Obama presented the debate as a clash between political ideology and scientific progress. And he claimed that the majority of Americans - from across the political spectrum, and of all backgrounds and beliefs - were in agreement that this research should be pursued.
This time he may have won the argument. But every time he encroaches into an area that concerns what used to be called the "moral majority" he risks sparking the cultural war he is desperate to avoid.