With my two kids in tow on Saturday, the main goal was finding some suitable flowers for Mother's Day, not talking about the Presidential race.

But when I ran into the one-time counsel to President Lyndon Johnson at a farmer's market, I figured I couldn't let my opportunity pass.

Was the talk of a possible "dream" ticket of Barack Obama and Hillary Clinton starting to remind him of JFK and LBJ?

"They really were oil and water," referring to JFK and LBJ, said Harry McPherson, Jr., who was counsel for Johnson both as Senate Majority Leader and later as President.

"Lyndon Johnson would be very proud right now," McPherson continued, "to see both a black man and a woman on the ballot."

Obama last week did not rule out having Clinton as his running mate, telling CNN, "She is tireless, she is smart. She is capable. And so obviously she'd be on anybody's short list to be a potential vice presidential candidate."

Of course, such a choice would certainly be controversial, especially since the two candidates have repeatedly clashed during the Democratic primaries.

McPherson recalled the bitterness that developed when John Kennedy chose Johnson as his running mate at the 1960 convention in Los Angeles.

"You had Joseph Rauh and others yelling 'Say it isn't so!'" said McPherson, smiling and shaking his head at the memory of that divisive time within the Democratic Party.

I'm sure there are some Obama supporters - maybe 'many' - who want no part of Hillary Clinton as the number two, especially since Bill Clinton gets included in any package.

Certainly there will be a lot more talk about an Obama-Clinton ticket, the longer that Hillary stays in the race, even as her chances become more and more and more and more remote for victory.

One of my early jobs on Capitol Hill was working for then Rep. Dan Rostenkowski (D-IL) who was of the opinion that LBJ was by far the better President than JFK.

In 1982, my summer internship partially turned into a lengthy research assignment to prove that point, that LBJ's legislative accomplishments were of much more import than Kennedy's, as two decades later there were still people fighting the JFK-LBJ fight.

Are Obama and Clinton the 'oil and water' of 2008?

Stay tuned.