"HE IS ONE of us," Bob Dole's campaign proclaims in Iowa -- unlike you-know-who, of Greenwich, Conn., Andover and Yale. Let's look at our tax returns for the last 10 years, says George Bush, confident that you-know-who and his Cabinet-secretary wife have been hauling in more money in recent years than the Bushes.

In other countries, successful people stress -- or invent -- connections to nobility: the French tittered when they learned that the d'Estaing was added to the former French president's name by an upwardly mobile Giscard not so many decades ago. In the American countertradition, William Henry Harrison, born on a grand James River plantation, was depicted in a log cabin drinking hard cider in the 1840 campaign. This year Bob Dole is basing much of his campaign in Iowa on the indisputable facts that he grew up in a small town in Kansas, went to public schools, came from a family of modest income and, after being grievously injured in World War II, worked himself up to his present position. Therefore, suggests the Dole campaign, he can understand the problems of the ordinary Iowan. To which Mr. Bush responds by suggesting that Mr. Dole, after 27 years in Congress and with a comfortable six-figure income, is insulated and remote from the ordinary American.

A silly argument all around. Voters know that anyone who has risen far enough to be a plausible candidate for president lives a life rather different from their own. They know also that politicians need to gain some understanding of how ordinary people and people with disadvantages live. Some will be able to draw on their own experiences more than others -- Mr. Dole, for one. But for any politician such understanding must come at least partly from the exercise of a sympathetic imagination. Franklin D. Roosevelt, with a physical disability more serious than Mr. Dole's and a family upbringing more insular than Mr. Bush's, convinced most Americans he understood them. Mr. Dole, with his Capitol Hill insider instincts, and Mr. Bush, with the prep school element of his background, both have a way to go to match FDR's example.

Anyway, you can't just proclaim that you understand how voters live. You have to show them you do as you discuss real issues. Both Mr. Dole and Mr. Bush have done that sometimes. They should both quit trying to suggest that the other guy is too rich to be president and give their sympathetic imaginations some exercise instead.