Once again, America’s leading political dynasties are holding high the family standard in an election year.

In Massachusetts, another Kennedy is racing toward Congress. This time, it’s Democrat Joseph P. Kennedy III, the grandson of the late Robert F. Kennedy, hoping to fill the vacancy of retiring Rep. Barney Frank.

“I’m very proud of my family’s record of public service to the Commonwealth and the country,” the young Mr. Kennedy has said. I don’t doubt his desire for service, but he’s also trading on the family name – and fundraising and other powers and privileges that go with it. That’s not what the Founders envisioned for the new republic.

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Meanwhile, in Texas and Florida, the Bushes are using their endorsement clout in an attempt to wrap up the messy Republican primary. It’s time for “the party to get behind” Mitt Romney, former President George H.W. Bush says.

His wife, Barbara – who referred to her son George W. as “the chosen one” before he even became president – has recorded a robocall for Mr. Romney’s campaign. Jeb Bush, another son and a former governor of Florida, has also endorsed Romney.

(A reasonable question: If Romney loses to Obama, will Jeb run in 2016? It’s a job he has said he has wanted since he was a kid.)

The United States has seen its share of political families: the Adamses, at the beginning, and in modern times, the Browns of California; the Cuomos of New York; the Daleys of Chicago; Ron Paul and his son Rand, now a US senator from Kentucky; not to mention Romney and his late governor father, George.

But over the past half century, no two families have been as powerful as the Bushes and Kennedys. They share deep New England roots and a seeming sense of entitlement to the White House.

The Kennedy taste for dynastic prerogative has at times been shameless. Sen. Robert Kennedy challenged a sitting president of his own party and tried to seize the presidential nomination – seeking to recapture his brother John’s lost legacy and rekindle the myth of Camelot. (Parallels can be drawn with the younger Bush president in attempting to finish off his father’s war with Saddam Hussein’s Iraq.)

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Even after the Kennedys suffered two assassinations, the family’s ambition continued to soar. Brother Edward tried (and failed) to unseat his party’s president, Democrat Jimmy Carter. So strong was the family’s belief that the White House belonged to them, that a defeated Teddy petulantly refused to shake hands with President Carter at the 1980 Democratic convention.

The youngest Kennedy brother never made it to the Oval Office, but he helped Barack Obama get there, acting as kingmaker along with his niece Caroline, as they pointedly favored Mr. Obama over Hillary Rodham Clinton (from a would-be dynasty).

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This practice of hereditary ambition and home-grown royalty betrays a basic premise of the American Revolution, “that all men are created equal.”

Andrew Jackson’s defeat of incumbent John Quincy Adams swept away much of our earlier faith in ruling families, and successive waves of immigrants made a mockery of it.

The Europeans spent centuries, sometimes knee-deep in blood, eliminating czars and kings.

Yet in the past 50 years in America, we have had to ride out allegations of rape, manslaughter, drug abuse, infidelity, and drunkenness in our “royal families,” overlooking all this on the medieval assumption that those with better bloodlines are somehow beyond reproach or the law.

And, like kings of old, today’s royals seek to maintain position and power by plying supporters, friends, and family with gifts, whether they be tax breaks or cabinet posts. At their peril, they forget that stability in any kingdom involved a delicate balance between the crown and nobility, and the people.

The republic could again use the same disdain for pretense employed by an earlier patriot who once said he wished that “wadding of the cannon fired to salute President [John] Adams would hit him in the seat of the pants.”

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The progeny of political families will likely ever seek political power – and the public may well respond with a certain star-struck awe and hope for favorable treatment. But in this country, we ought to judge a candidate on merit. That’s what we were raised on.

Walter Rodgers is a former senior international correspondent for CNN.

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