By Knight Kiplinger, Editor Emeritus March 5, 2008 I'm beginning to hear more and more people compare Barack Obama to President John F. Kennedy. Not surprisingly, those making this comparison are mostly too young -- or too little schooled in history -- to know how invalid the comparison really is. Yes, there are similarities in rhetorical style. As Kennedy did in 1960, Obama is inspiring idealistic young voters to get involved in the political process and public service. Like Kennedy, Obama is seeking to unite Americans of disparate races and backgrounds. Like Kennedy, Obama is a young man of great charisma and personal charm, but with a modest record of legislative accomplishment in the Senate, due to brief service. And that's where the Kennedy-Obama similarities end. On the substance of their positions and policy inclinations, the differences are enormous. Of course, today's world is very different from the 1960s, and who can say for sure how Kennedy would have responded to today's issues? Kennedy was a tax-cutting, free-trading, tough-on-communism candidate who won a razor-thin victory in 1960 by accusing incumbent President Eisenhower and Vice President Richard Nixon of letting the Soviets open a lead on the U.S. in nuclear missiles. Kennedy called for a big military build-up to close the "missile gap," and it began early in his administration. In three years of very few legislative successes before his tragic murder in 1963, Kennedy did win enactment of major reductions in U.S. tariffs. He was a passionate believer in free trade. Obama, by contrast, is trying to win delegates in blue-collar states by threatening to roll back provisions of NAFTA, which President Bill Clinton championed but couldn't have pushed through the Democratic Congress without significant GOP support. Candidate and President Kennedy advocated deep cuts in income tax rates, and they were enacted by Congress after his death -- the boldest tax reduction until Ronald Reagan's cuts 20 years later. Those 1964 cuts dropped the lowest rate from 20% to 16%, and the top rate from a confiscatory 91% to a breathtaking 77%. Obama, by contrast, proposes raising the top income tax rate back up to 40% and pushing the capital gains and dividend rate from today's 15% to something between 20% and 25%. Candidate Kennedy called for an accelerated space exploration program to enable the U.S. to catch up with and eventually surpass the Russians. Kennedy lived to see American astronauts in space by 1962. Obama, by contrast, seems skeptical of the value of space exploration and would seek a slowdown in certain programs. Kennedy's administration was full of Cold Warriors who were committed to thwarting Soviet and Chinese expansion in every sphere. In Cuba, he supported what today is called "regime change" and "preemptive war." The Bay of Pigs invasion of Cuba to overthrow Fidel Castro was conceived by the Eisenhower administration, but a recently inaugurated Kennedy approved going ahead with it; it was an embarrassing failure. In a high-risk act of brinksmanship -- and his greatest foreign policy triumph -- Kennedy in 1962 imposed a naval blockade on Cuba, turned back a Soviet ship bringing nuclear missiles to that island off Florida, and forced the Soviets to remove recently installed missiles. In the three years of his presidency, Kennedy backed the anti-communist regime in South Vietnam -- as did his Republican predecessors -- and introduced the first American combat troops there. (The big escalation of America's commitment in Vietnam, of course, would come under Kennedy's successor, Lyndon B. Johnson.) While Kennedy was comfortable with projecting America's military might throughout the world, Obama is a leading proponent of a much more limited use of that might. He supports the campaign in Afghanistan to keep the terrorist-sponsoring Taliban out of power. But he believes the toppling of Saddam's brutal regime in Iraq was unnecessary and a terrible waste of U.S. resources. To sum up: By today's standards, John Kennedy would be a moderately conservative Democrat, while Obama -- by all analyses of his Senate voting record -- is on the left wing of his party, on issues both domestic and foreign. John F. Kennedy's real ideological descendant in the Democratic Party is Bill Clinton, not Barack Obama. Hilary Clinton falls somewhere in the middle. She once supported the conservative programs of her husband, such as welfare reform, free trade agreements and a tough stance against Serbian aggression in the Balkans. Now, to try to win the Democratic nomination, she is drifting to the left, criticizing NAFTA and calling for higher taxes on the wealthy. If she manages to get the nomination, she would probably move back to the middle, as Bill Clinton did in 1992, to woo independents. If Obama wins the nomination, he would be as liberal a Democratic standard-bearer as George McGovern in 1972, Walter Mondale in 1984 and John Kerry in 2004. Compared with the winning moderate Democrats of recent years --Jimmy Carter in 1976 and Bill Clinton in 1992 -- the liberals fared badly, but perhaps today -- after 16 years of moderate-to-conservative administrations under Clinton and Bush -- Americans want something very different. Might Obama modify his current positions if nominated? Perhaps we'll know very soon. And how might he govern if elected president -- like a John Kennedy, a Bill Clinton, or something that tracks closer to his current more-liberal positions? It is impossible to predict. We do know that the realities of governing -- dealing with a strong-willed Congress, even of one's own party, and grappling with unforeseen international crises -- change leaders enormously.