One of the more remarkable American political developments of the last two months has been the Reagan family's distancing itself from George W. Bush even as Bush patterns his tax-cutting cowboy presidency not after his own father's, but after Reagan's. That's with the exception of Michael Reagan, who is not Nancy's natural son and who managed to find a career for himself by cashing in on his name to spout some of that ubiquitous syndicated right-wing radio gab. But as we all know by now, Ron Reagan spoke to the Democratic National Convention to assail the Bush administration's right-wing pandering in opposing new embryonic stem cell research, which conceivably could produce a cure for Alzheimer's and other diseases. He was speaking in that specific regard also for his mother, Nancy. She had previously publicly decried the loss of precious time in research. The stem cell issue has become such a concern for the Bush campaign that it dispatched the other day its most compassionate face, Laura's, to make sure everyone understands that some stem cell research is continuing - on lines existing before the fall of 2001 - and that reports of imminent cures are very premature. Now Nancy, at last report, has rebuffed pleas from friendly Republican emissaries that she appear at the Republican National Convention at the end of the month, immediately after the showing of a videotaped tribute to her beloved Ronnie. She is said to be still shaky from losing her husband and disinclined to be used to undercut her son's argument before the Democrats and the nation on stem cell research. Michael has been quoted as telling Fox News that Ron can do no wrong as far as Nancy is concerned. And the widow reportedly was highly offended to learn that during the week of her husband's funeral, the Bush campaign was testing television commercials seeking to take advantage of the outpouring of esteem for the former president. Reports are that Mrs. Reagan will do her Republican duty to say something nice about Bush, or show up somewhere with him, later in the campaign. It may test her old acting skills. It's not merely that she has taken recent exception to George W. It's also that she always was more Ronnie's girl than a Republican girl. Sort of like Laura to George W., I'd suggest. Nevertheless, with the election all about swing votes now, the Republicans plan to put forward such a centrist and moderate veneer in New York City at the end of the month that the Bush presidency, the most conservative of the modern era, may not become recognizable - until Bush and Dick Cheney speak late in the week. It so happens that the Republicans' biggest stars, and the people they see an advantage in showcasing during prime time at the convention, are pro-choice on abortion and generally to the left of the president and the Republicans in Congress, none of whom, it appears, will get prime time slots. Keynote speakers will be Rudy Giuliani and New York Gov. George Pataki, old Rockefeller Republicans; John McCain, who can scarcely abide Bush some days; and Arnold Schwarzenegger, whose views on prevailing social issues are in line with those of his in-laws, the Kennedys and Shrivers. The Democrats gave us generals. Now the Republicans give us social consciences. Maybe 10 percent of the electorate remains pivotally undecided and potentially willing to play these games of charades.