The change in administrations brings further examples of a subject I addressed here: the power of a president or a state governor to make certain decisions on their own, without submitting them to the legislative branch.
Constitutional and statutory law give those executives the authority to do certain things.
Those aspects of federal abortion policy that are in this category, have become a tennis ball that is batted back and forth between Republican and Democratic presidents. Party positions on that issue had become solidified by the 1980s, after which the Democratic Party has nominated only pro-choice presidential candidates, and the Republicans have chosen only pro-life nominees. As the electorate has chosen alternating Republican and Democratic presidents, each White House newcomer has quickly switched abortion policy to his party's point of view.
President Obama is expected to follow suit, shortly.
The president of my alma mater likes to tell the story of visiting a Middle Eastern country, and reviewing a brief summary of facts about that country. Under the heading of "government", the document read "by decree". His democratic sensibilities were offended. But, when he later became a college president, he realized the advantages he would have had, had he been able to rule by decree.
Similarly, all of our presidents are democratic, even if they're Republican. But I'm sure they appreciate the extent to which they're able to rule by decree, rather than submitting their ideas to the slow legislative mill at the other end of Pennsylvania Avenue.