Longtime GOP pollster and political strategist Frank Luntz told CNBC on Tuesday he will be closely watching the results in North Carolina, Florida and Ohio, describing the trio of states as key bellwethers in determining the election outcome between President Donald Trump and Democratic nominee Joe Biden.”If Donald Trump wins all three of them, he’s going to be in this,” Luntz said on “Squawk Box,” as Americans who haven’t already voted go to the polls on Election Day. “If Biden wins even one of those three, it’s Biden’s presidency,” Luntz added.Biden holds slight leads over Trump in Florida and North Carolina, but the president is within striking distance, according to the CNBC/Change Research poll released Monday. The survey did not include Ohio, which Trump won in the 2016 election by 8 points. He also took Florida and North Carolina en route to an upset victory four years ago.If Trump is able to win these three critical states, the race may then boil down to the results in Pennsylvania “because they’re going to take the longest to count [votes],” Luntz predicted. “We will not know a winner in Pennsylvania for at least the next 48 hours, perhaps 72 hours.”However, Luntz said he believes Ohio, North Carolina and Florida are so critical because they may have results by early Wednesday morning, thereby offering a strong glimpse into Trump’s overall chances to win a second term.Trump spent election eve at rallies in North Carolina, Pennsylvania, Wisconsin and Michigan. Biden on Monday was in Ohio and Pennsylvania.In an election with a surge in mail-in voting due to the coronavirus pandemic, Luntz urged Americans to be patient as states tabulate results. With nearly 100 million votes already cast early, states have different rules on when election officials can process the votes and then actually count them.”I think that this is not going to be resolved in 24 hours. I don’t think it’s going to take until Dec. 1,” he said. “But I do think it’s going to take two or three days and people may get the wrong impression based on which votes are counted early.”Ed Mills, a Washington policy analyst for Raymond James, said Wall Street investors have in recent days focused on Pennsylvania as a “potential tipping state.” In an interview earlier on “Squawk Box,” Mills struck a similar tone as Luntz, noting the likelihood that results take a few days to come into focus. While polls show a Biden lead, “whether or not that is right or not, we have to wait until tonight, maybe for a couple days, especially in Pennsylvania, where a number of counties will not start counting a single absentee ballot until the day after the election,” Mills said.