Senator Lieberman’s decision to flash his famous independent streak by crossing party lines and endorsing Senator McCain for president might seem to take some wind out of the sails of the idea we have been nursing of a presidential campaign by the mayor of New York, Michael Bloomberg. If Mr. McCain fills the niche of the candidate who can occupy the centrist terrain and attract independents such as Mr. Lieberman, the Democratic Party’s 2000 vice presidential nominee, what’s the need for Mr. Bloomberg?

Well, let’s just say, it’s still early. On the eve of today’s endorsement, a Lieberman aide told us that Mr. Lieberman’s endorsement of Mr. McCain would likely not preclude Mr. Lieberman’s endorsement of another candidate, including a third party one, should Mr. McCain not win the Republican nomination.

There are plenty of scenarios about which to speculate here. Not a vote has yet been cast. But wouldn’t it be something, were the Republican nominee to end up being Governor Huckabee, to see Senators McCain and Lieberman offering their own joint endorsement of a Bloomberg for president campaign?

Mr. McCain is clearly hoping it doesn’t come to that. But he and Mr. Lieberman have both run and lost before and know that there are a lot of things that can go wrong in a presidential campaign. An independent campaign by Mr. Bloomberg could bring to bear hundreds of millions of dollars that Mr. McCain’s campaign, hampered by the ill-conceived fundraising limits he legislated, does not have available to deploy.

It is a highly fluid race at the moment. While just weeks ago everyone was expecting an early decision just short of a coronation, the front-runners Mayor Giuliani and Senator Clinton are both struggling to regain their momentum after suffering from overexposure. At this time last time, everyone thought Governor Dean would be the Democratic nominee. It may be Mr. McCain’s moment at the moment, but the campaign is still young.