People are already comparing Barack H. Obama with John F. Kennedy but I'm not sure that all aspects have been considered. Lets look at the two.
First, the similarities. They are both charismatic and both are considered minorities (prior to 1960, an Irish/Catholic was considered unelectable). By 2008, Obama will equal Kennedy's four years in the Senate. They both positioned themselves as Washington outsiders who would shake things up. That's about it for similarities.
There are some significant differences. Kennedy was an anti-communist hawk. One of his major issues was the "missile gap" meaning that we had allowed the USSR to build more missiles than we had (once elected he found that this was not so). Obama is running as a dove. He was always against invading Iraq. Where Kennedy was fiercely pro-America, Obama is a multi-nationalist. Obama has been quoted that, as a post-Baby Boomer, he has moved beyond the concepts of good and evil.
Kennedy was far more conservative than today's mainstream Democrats. It's hard to imagine any modern Democrat proposing a tax cut but Kennedy did, providing Reagan with evidence that tax cuts could stimulate the economy and increase overall tax revenues. Obama's liberal voting record indicates that he is closer to Ted Kennedy.
There are several reasons that Obama might not want to be associated with JFK. Kennedy never gave much support for civil rights. His outsider status meant that he didn't really know how Washington works and most of his agenda languished.
Then there was Cuba. First Kennedy presided over the Bay of Pigs. Then he brought the world to the brink of nuclear war during the Cuban Missile Crisis. Plus he sent the first troops to Viet Nam.
Kennedy's personal life was nothing to emulate. Even assuming that most of the stories about his affairs are exaggerations, he did have some well-documented mistresses. This may have left him open to blackmail by J. Edgar Hoover. Kennedy suffered from Addison's Disease. Today there is a safe, effective treatment but this did not exist in the early 1960s. Kennedy covered up how ill he actually was but, between the Addison's treatments and the pain medication for his back, there is question about his mental state.
All things considered, Obama might want to run from the Kennedy comparisons.