stock images of 2020 presidential candidates Joe Biden and Donald Trump (Images: Shutterstock)

As Election Day arrived, political analysts and strategists were quick to air their predictions on whether an election outcome will be known quickly or drag on, and on how the Senate and House races will shape up.

“It could take days for officials to count mail-in ballots — and then there will be recounts and inevitable lawsuits that could take weeks to resolve,” Greg Valliere, chief U.S. policy strategist for AGF Investments, said in his Tuesday morning email briefing. “It’s 2020 after all; expect the unexpected.”

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Democratic strategist James Carville said Monday on MSNBC, however, that “we’re going to know the winner of this election by 10 tomorrow night. What people are doing is unnecessarily scaring people and making them unnecessarily nervous.”

Carville, the lead strategist during former President Bill Clinton’s campaign, added: “I am not the least bit concerned about the outcome tomorrow night, and I’m not the least bit concerned that we’re going to have to wait weeks and months to know what the result is.”

Andy Friedman, founder and principal of The Washington Update, told ThinkAdvisor via email Tuesday that “Trump has a better chance to win than people realize,” and “I think he will win Florida.”

Pennsylvania, however, “is a toss-up,” he said. “If Trump wins Pennsylvania as well, he needs to win two of Michigan, Wisconsin, Arizona, and North Carolina to win the election.”

Easy calls, according to Valliere, are that the Democrats will maintain control of the House, probably picking up a few more seats. “They presently have a 35-seat majority. Joe Biden will easily win the popular vote, perhaps by 5 or 6 million votes.”

The “toughest call” is the Senate, Valliere said. “The Senate, with 53 Republicans and 47 Democrats, still looks very close. Republicans may lose four of their seats while the Democrats lose only one — creating a 50-50 tie that the Democrats would break. Or the Democrats could gain control by 51-49. Or we may have to wait for a runoff election on Jan. 4 in Georgia.”

Legal challenges may become moot if Florida or North Carolina “break early tonight for Biden,” Valliere said.

But President Donald Trump is likely to challenge a close outcome, Valliere continued, “with Attorney General Barr taking a case all the way to the Supreme Court. A final ruling may not come until December, which would not be a welcome development for the financial markets.”

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The latest CNBC and Change Research “States of Play” election poll, released Tuesday, shows the race tightening in at least three crucial states.

The poll, conducted Oct. 29-Nov. 1, shows former Vice President Joe Biden leading (50% versus 46%) across all six major battleground states (Arizona, Florida, Michigan, North Carolina, Pennsylvania and Wisconsin), a position he has held since mid-summer.

Biden’s lead, however, is narrowing in some states, most of which are tied within the margin of error.

Since the last CNBC/Change Research poll two weeks ago, Trump picked up three points in Florida (51% Biden versus 48% Trump), two points in Arizona (50% Biden versus 47% Trump) and one point in Wisconsin (53% Biden versus 45% Trump).