Philadelphia Mayor James Kenney's warning that Pennsylvania's largest city may not have a final vote tally for several days shows jurisdictions eager to institute mass mail-in balloting were woefully unprepared for it, Marc Thiessen told "Bill Hemmer Reports" Monday.

"It shows how unprepared some of these states are, particularly a key state like Pennsylvania, for the deluge of ballots coming in," said Thiessen, a Fox News contributor. "The Democrats have pushed for this early voting and mail-in voting. State laws are unprepared."

"Never in the history of this city have so many people voted by mail," Kenney wrote in an open letter released earlier Monday. "By law, staffers are not allowed to start opening and counting these ballots until Election Day itself. That means getting a tally of mail-in ballots will easily take several days. This may determine the outcome in Philadelphia, and in the Commonwealth as a whole."

"It makes perfect sense not to start counting the ballots are sorting them or touching them until Election Day if you only have a small number," Thiessen added, "but if you have a massive number, then it's an entirely different matter, so I think Pennsylvania is going to drag this election out."

BIDEN'S PENNSYLVANIA LEAD SHRINKS IN FINAL DAYS OF RACE: POLL

Last week, the Supreme Court turned away a Republican Party bid to block a state court order allowing election officials to accept absentee ballots for three days after Election Day. The order was originally upheld in a party-line State Supreme Court decision in September.

The Late-arriving ballots will be counted separately for the sake of “effective and clear election administration in Pennsylvania,” Secretary of the Commonwealth Kathy Boockvar said in October. Hours before the Supreme Court declined the GOP plea, Boockvar told counties to set those ballots aside and not count them. 

Meanwhile, Philadelphia District Attorney Lawrence Krasner warned last week he has "a jail cell" prepared in case of aggressive behavior from unauthorized poll watchers supportive of President Trump.

Turning to the rest of the electoral map, Thiessen remarked that Florida has been allowed to count its mail-in votes for several weeks and could be the "canary in the coal mine" on election night.

"A lot of the early voters that you showed on your screen, their votes are counted and they are going to get numbers in pretty early," he said. "How Florida goes will tell us a lot about how the rest of the country goes. If Donald Trump loses Florida, the election is probably over. If he wins Florida comfortably, by three points, that means ... he's got a very good chance of winning the whole thing."

"If it's narrow, it means we are going to be litigating Pennsylvania for the next month."

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During the segment, former DNC Communications Director Mo Elleithee added that he sees Florida, North Carolina and Georgia as three competitive swing states that should have their final counts in earlier than others.

"Then there's going to be other states, Pennsylvania, Ohio, and a number of others that are close and will likely remain close," he said. "We will not know who wins for days afterward, and that's OK."

The Associated Press contributed to this report.