Who Will Win the Presidential Election?

This presidential election, unlike any other in recent history, defies conventional political calculations. For that reason, Americans are advised to ignore the polls, pundit predictions and electoral math. The truth is there are too many variables to accurately forecast the election outcome.

The latest stunning twist in this bizarre election was the Federal Bureau of Investigation (FBI) announcement last week that it was reopening its probe into Hillary Clinton's email scandal.  Never in American history has a candidate for the presidency been investigated twice by the FBI.

This development and unproven allegations of Donald Trump's sexual misconduct have thrust the election into unchartered waters.  For the first time in recent memory, surveys show voters are decidedly despondent and disgusted.  Some Americans say they plan to vote for neither candidate.

An ABC News tracking poll identified enthusiasm gaps for both candidates.  "As a percentage of voting age population, it (turnout) will be low, probably lower than the past four or five presidential elections," according to Matthew Dowd, an ABC News political analyst.

There are other variables that are even harder to quantify.  Both candidates have corpulent negative favorability numbers that have never been seen in a presidential race.  Will that be enough to motivate Americans to vote against one candidate or the other?

Questions also have been raised about turnout among African-Americans and Hispanics.  In the 2012 presidential election, turnout among blacks topped 66 percent, eclipsing 2008's 65.2 percent. Hispanic turnout in 2008 reached a historic 49.9 percent, but slid to 48% in 2012.

These two demographics groups voted overwhelming for Barrack Obama. Ninety-five percent of African-Americans voted for the president in 2012.  The president won 82 percent of the Hispanic vote that year.  He racked up similar margins in 2008.

Will the record turnout and lopsided margin for Mr. Obama be the same for Ms. Clinton?  Especially in swing states, African-Americans and Hispanics will hold the key to victory. Any slippage in turnout or margin will open the door for the Republican Donald Trump.

Right behind minorities in importance are young people aged 18-29. These adults turned out in record numbers in 2008 and 2012.  More than half (51%) of young voters flocked to the polls in 2008, the highest since the election of 1964.  Will these fickle voters remain engaged this year?

In both elections where Mr. Obama was on the ballot, young adults gave him comfortable margins. He collected 61 and 62 percent, respectively, in the elections of 2008 and 2012.  Will young voters support the Democrat nominee at those same levels this year?

Answers to those questions will go a long way in deciding this presidential election.  However, there is one group that has escaped media attention that likely will be the most influential in determining the next president.  They are unmarried women.

According to the Voter Participation Data Center, unmarried women are the country's fastest growing demographic.  More than 58 million single women are eligible to vote this year.  The is the first time in American history that voting-age single women outnumber married women in an election.

In nine of the battleground states, including Colorado, Florida and Virginia, the number of unmarried women eligible to vote this election exceeds married women.  That is significant because these singles have been among the most reliable Democrat Party supporters in past presidential elections.

In 2008, Mr. Obama carried unmarried women by a thirty-point margin, 66 to 34 percent.  The vote for the president in 2012 was even more out of balance.  Mr. Obama received 71 percent of the votes recorded by unmarried women, a 42 point margin over his Republican challenger.

Although it is never fair to generalize about an entire group, most single women have been at odds with Republican positions on abortion, contraception and female health issues.  The charges against Donald Trump involving alleged sexual misconduct won't help him with these women either.

If single women turn out in droves, it will be a good sign for Hillary Clinton, if past voting patterns hold.  Those are big IF's, considering Ms. Clinton's own trust issues with voters.  It is just another unknown in an election sprinkled with question marks.

For that reason, the only accurate prediction about this election is that it is unpredictable.