Alice Roosevelt Longworth, Teddy Roosevelt’s irrepressible, sharp-tongued daughter, once said of the Kennedys that the world had not seen a family like them since the Bonapartes.

Alice was in no position to make wisecracks about ruling families. She belonged to one herself. Her father and Franklin Roosevelt were distant cousins. Not only that, Teddy was Eleanor Roosevelt’s uncle.

For a nation founded on the principle that all men are created equal, this country has produced a remarkable number of princely houses. TR and FDR were related. John Quincy Adams, our sixth president, was the son of second president John Adams. Benjamin Harrison, the 23rd president, was the grandson of ninth president William Henry Harrison. And, of course, President George W. Bush, our 43rd president, is the son of George H.W. Bush, our 41st president.

The Taft family of Ohio produced a president -- William Howard Taft, who served as Chief Justice of the U.S. Supreme Court after he left the White House –- and also three senators, two representatives and a lieutenant governor. The Frelinghuysens of New Jersey have served in either the House or Senate for six generations. Then there are the Chafees or Rhode Island and the Bayhs of Indiana. I've already mentioned the Kennedys.

Stephen Hess of the Brookings Institution has calculated that as of the mid-1990s, about 700 U.S. families had sent two or more members to Congress. According to him, political dynasties “are all over the place.”

In fact, Sunday’s Detroit Free Press calculated that if Hilary Clinton wins the White House in 2008, and serves two full terms, then by the year 2016, the United States will have been governed for 28 years by either a Bush or a Clinton in the White House. That would be nearly 12 percent of U.S. history to that point. It would also be nearly as long as the Wars of the Roses, the bloody struggle between the rival houses of York and Lancaster that devastated medieval England between 1455 and 1487.

“What has happened to the American republic?” asks University of Virginia political scientist Larry Sabato. “How does it differ from a banana republic where a couple of dominant families often run everything for generations?

Professor Sabato thinks that American voters may be too fearful of change. He may be right. Perhaps we should spend tomorrow not celebrating the signing of the Declaration of Independence, but asking if this country needs another revolution to free itself from hereditary privilege and decadent royalty.