John Kerry running for president in 2020 wouldn't be the craziest thing ...

Washington (CNN)John Kerry -- remember him! -- made a little news during an appearance on "Morning Joe" Wednesday.

Check out this exchange between the Democrats' 2004 nominee and "MJ" anchor Joe Scarborough:
Scarborough: You're tan, you're rested and ready. You're younger than everybody else talking about running for president of the United States. Is it Kerry 2020?
Kerry: I don't have any plans right now, honestly.
    Scarborough: That's not a denial.
    Kerry: I'm not thinking about it.
    Scarborough: You're younger than most people talking about running right now in the Democratic Party.
    Kerry: Thank you so much. You're a troublemaker.
    None of Kerry's responses -- as Scarborough rightly notes -- is a "no." And, yes, for the billionth time, when a politician -- especially one who has run for president before -- refuses to rule out running again, it's on purpose.
    That's not to say Kerry is running -- or even actively considering running. Just that he doesn't want to shut any doors that he might want to peek behind over the next three years.
    And, while I don't expect Kerry to run, it's not crazy that he would consider it.
    Kerry is a longtime senator. A secretary of state. The Democratic nominee in 2004. This side of Joe Biden, he probably has the deepest resume of domestic and foreign policy experience of any candidate on the long list of 2020 contenders.
    Scarborough is right, too, about the fact that Kerry's age -- he's 73 -- doesn't look like as a big an issue in 2020 as it might be in other elections. Biden is 74. Bernie Sanders is 76. Elizabeth Warren is 68. And that, ladies and gentleman, is the top tier of the 2020 field against President Trump!
    His past presidential bid also means that unlike everyone in the field other than Biden, Kerry has been seriously vetted for the top job. (Say what you will about Sanders but he did not receive a full vet from the public in 2016.) In an election which is likely to be every bit as nasty and personal as the 2016 contest was, putting forward a candidate whose warts are already known could be very smart.
    In May, CNN's Michelle Kosinski observed that Kerry went out of his way in a speech at a private gathering to say that his four years at the State Department might not be his "last" position in the US government. He didn't seem to be joking.
    His remarks, as Kosinski reported, were the "hopeful chatter of the rest of the evening" among the attendees.
    Now for the cold dose of reality.
    All of the things I wrote about Kerry above are true. But my strong sense is that none of that would matter if he decided to run for president again. Democrats would remember that Kerry lost what was seen as a very winnable race in 2004 -- and in so doing delivered a second term to George W. Bush.
    For lots of other people, Kerry was and will always be a Swiss-cheese-on-the-cheesteak-ordering, Lambert Field saying, French speaking, wind-surfing northeastern elitist. And, in a potential race against unlikely populist hero Donald Trump, that's a major problem.
    Then there's the contrast between Kerry -- a lifetime politician and author of the famous/infamous "I actually voted for it before I voted against it" line -- and Trump, who continues to portray himself an outsider to Washington and the political process. Kerry virtually oozes "politician" -- with everything from the way he talks to the way he looks -- and you can bet Trump would do everything he could to highlight that fact.
    Given the size of the potential field and the Democrats either already running or thinking about running -- John Delaney, for the win! -- it's totally within reason that Kerry wouldn't totally close the door just yet. His would be far from the longest-shot candidacy in what is going to be a massive Democratic field.
    But, the case against Kerry running again -- for himself and for the party -- is still considerably stronger than the case for him to try for the brass ring a second time.