What a difference a couple weeks makes! Back on November 18, a local news site reported that it was absolutely certain that Senator Mark Leno would be challenging Ed Lee in San Francisco's 2015 mayoral election. On Saturday, however, Leno made it clear: he would not be running.

"LENO TO CHALLENGE SF MAYOR LEE IN NOVEMBER," trumpeted local news site Beyond Chron, in a report that was also published by San Francisco Magazine.

"State Senator Mark Leno will announce after Thanksgiving that he will run against San Francisco Mayor Ed Lee in the November 2015 election, Beyond Chron has learned from multiple sources," the piece began, saying that "Leno will portray Lee as a cheerleader for the very forces that are making San Francisco less affordable and economically diverse. If you feel that San Francisco is moving in the wrong direction, Leno wants your vote."

We here at SFist picked up the report too, noting even as we did that an October SFist poll had Leno beating Lee 86.83% to 13.17%. But apparently an SFist poll wasn't enough to convince the current state Senator to actually run, as Saturday the Chron's Matier and Ross (yes, the same folks said Leno was mulling a run a few months ago) quoted Leno as saying "After significant consideration and examination, I have determined that now is not the time for me to enter the race."

Though Leno had reportedly been "repeatedly approached by various labor, business and neighborhood leaders upset about the direction of the city under Lee...it also became clear to Leno that while there was a significant bloc of voters who wanted change, it wasn’t large enough to oust a sitting mayor," M&R say.

At least, that's their take. BeyondChron's Randy Shaw, who also penned the earlier report that said Leno would run, has another idea: that Leno was all set to run, but basically chickened out when he saw Lee was up for a fight.

Now, keep in mind that BeyondChron, a publication from San Francisco’s Tenderloin Housing Clinic, is well-known for its constant championing of Mayor Ed Lee, allegedly because "Shaw quietly gets tremendous city support — including big infusions of public funds — for his projects and initiatives." So, huge grain of salt with any of BeyondChron's analysis.

Got out the shaker? OK, so Shaw's piece from today says that "In response to Leno’s potentially tough challenge, Mayor Lee began campaigning as if it were the fall of 2015, not still 2014. And the mayor’s quick launching of a campaign and fundraising team sent a message to Mark Leno that Lee was ready to rumble and this race would be far more daunting than previously appeared."

So, your choice: Leno decided not to run because (despite a non-SFist poll forecasting a Leno over Lee victory) he didn't think he could get the votes — or he decided not to run because he wasn't up to the fight. Whatever the reason, it's not going to happen. So now we're back to the question we last raised on October 14, before this whole Leno charade began: So Who's Going To Run Against Ed Lee?