(cross-posted at mydd)

It is not often in politics that you can get a knock-down argument that clearly should persuade the vast majority of the electorate, but I believe circumstance has provided the Barack Obama campaign with such an argument in his primary battle with Hillary Clinton.

It is an argument that starts from ground that most of the democratic primary voters share and leads to the conclusion that Obama is, at this point, incontrovertibly the candidate that should be supported by superdelegates and by the voters in the March 4th states.  I believe the argument is so strong and relatively obvious that it will percolate down to enough undecided voters that the nomination battle will be effectively over on March 4th after Obama takes Ohio and Texas.  But this diary is not about making a prediction; rather I intend to convince you that at this point, there is only one candidate for a good Democrat to support.