Governor Bill Richardson: "Whoever has the most delegates after Tuesday should be the nominee."

(CBS) New Mexico Governor Bill Richardson, a former candidate for the Democratic presidential nomination, predicted that the results of this week's primaries will decide the party's race.

“D-Day is Tuesday," he told Face The Nation host Bob Schieffer. "Whoever has the most delegates after Tuesday should be the nominee."

Richardson deferred from announcing a personal endorsement of either Hillary Clinton or Barack Obama (“I’m legitimately torn," between the two, he said), but suggested that the leader after this week's primaries will have the presumptive title.

He also called for a positive Democratic race rather than one marred by negative ads or name-calling. “We have to have a positive campaign after Tuesday," Richardson said.

"I think we've got to be ready for a very strong John McCain. Republicans are united right now. They don't have a divisive primary. It looks like the tone of our campaign is heading much too negative. And I want to see us after Tuesday basically come together and see where we are and move on to the general election.

"This campaign is getting much too negative. The American people want us to be positive. They want us to talk about issues. And I'm just worried that the tone of this campaign has gotten excessively negative. And it may hurt us in November.”