Mayor Bloomberg yesterday warned voters against confusing “charisma and presentation with substance” in choosing their leaders — a remark that could be seen as a jab at Senator Obama, whose soaring oratory and packed rallies have fueled his success in the presidential campaign.

The mayor made an abrupt detour into politics at an event in Lower Manhattan yesterday to unveil a plaque dedicated to the Super Bowl champion New York Giants at the site of their ticker-tape parade earlier this year.

Mr. Bloomberg defended the pomp and circumstance allowed for sports teams before turning, briefly, to electoral politics.

“When we are electing our leaders I think we have to apply a different standard,” he said. “And sadly we sometimes confuse charisma and presentation with substance, and that’s difficult for the voters to separate out but that is the great challenge in democracies every place in the world.”

The comments came two days after Mr. Obama and the presumptive Republican nominee, Senator McCain, snubbed the mayor’s bid to host a joint town hall meeting in New York’s historic Federal Hall. Mr. Bloomberg has pushed for the candidates to be specific in outlining their policy proposals and detailing exactly how they would pay for them.

At the same time, he has struck up a good relationship with Mr. Obama and introduced him before an economic speech at Cooper Union in April. He has been friends with Mr. McCain for years and has been mentioned as a possible vice presidential pick or Cabinet secretary for both candidates.

A City Hall spokesman said the mayor was not referring to Mr. Obama, although it was unclear what other candidates he could have had in mind.