One hundred days has been an important political milestone for at least a couple of centuries. It was first used to define the period between Napoleon's return to Paris after his escape from exile and his abdication following his defeat at Waterloo.

Closer to home it's been a description of the special session of Congress from March 9, 1933, to June 16, 1933, when Franklin Roosevelt pushed through legislation designed to offset the devastating effects of The Great Depression.

Because that session closely paralleled Roosevelt's first term as president (he wasn't inaugurated until March 4), the first hundred days of any administration has become a symbolic benchmark measuring its early successes and failures. Roosevelt himself is widely regarded for coining the phrase "first 100 days" in a July 24, 1933, radio address.

Since then the media has had a field day every four years detailing the track record of each new administration and making all sorts of predictions and pronouncements about what it all means.

We are now 100 days before the pivotal 2018 midterm elections. So what better time to look ahead to November 6 and begin to make our own predictions and pronouncements? Historically midterm elections have been bad -- sometimes disastrous -- for the party that occupies 1600 Pennsylvania Avenue.

Typically, the party that holds the presidency has lost more than 30 seats in the first midterm of the administration. That's more than enough, by itself, to overtake the Republican's narrow majority in the House.

Democrats have been telling us, since the election of Donald J. Trump along with a Republican Congress, that a giant "Blue Wave" is building steam offshore, ready to sweep across the land and carry with it huge majorities for them.

The only evidence of a looming aqua tsunami we've seen thus far are a couple of ripples here and there.

In several House special elections held since Trump was inaugurated, Democrats boasted that they'd roll to victory based on "resistance" to Trump. They lost every one.

They finally found the mark here in Pennsylvania when Conor Lamb took out Rick Saconne in a special election earlier this year. But Lamb wasn't a "resistance" candidate by any stretch. He even went so far as to say he wouldn't vote for Nancy Pelosi if he was elected.

That's a far cry from candidates like Alexandria Ocasio-Cortez, the New Yorker who defeated U.S.Rep. Joe Crowley, whom many saw as a potential replacement for Pelosi, in their Democratic primary.

She's an unrepentant socialist whose calls for "free" everything and for abolishing ICE mirror the far-left rhetoric of some other Democrats, including several here in the Keystone State.

Socialist candidates pose a serious problem for Democrats. Many of their leaders are now publicly expressing serious concern that left-wing nuttiness will drive independent and swing voters away from them and threaten to disrupt a unified base.

Midterm elections are "base" elections. That means that turning out each party's base voters is crucial to success.

Party unity is vital to winning in the midterms. The growing divide in Democratic ranks exposes a lack of unity. Democrats may believe that mere resistance to Donald Trump is enough to unite their base. The constant drumbeat from their socialist flank makes that far less likely.

Additionally, independents and "swing" voters tip the scales in many of the "battleground" districts that will determine control of the House. Those voters aren't attracted to calls for gigantic tax hikes, open borders or "sanctuary cities."

What looms over all of this are the two factors that will determine the 2018 midterms: Donald Trump and the U.S. economy.

The left will try to put every Trump tweet, verbal miscue and personal problem under a magnifying glass. They've been working that strategy for a year and a half now. Yet the president's approval numbers continue to climb. He's now eclipsed the approval rating Barack Obama had during his second midterm election.

Trump's numbers would be much higher were it not for the hiccups of his tweets and verbal miscues. There's one huge reason for that: the economy.

Bill Clinton's team famously told us, "It's the economy, stupid." They weren't wrong, but we're not stupid.

The Economy is humming. Economic growth is booming, far eclipsing the record of the past four years. Jobs are flourishing, unemployment is at its lowest in half a century, the stock market is soaring and people are taking home bigger paychecks.

Ultimately, people vote their wallets. They also vote on the current administration, both its policies and the personality of its leader.

Which side of that scale -- the president's sometimes polarizing style or a robust economy -- tips highest will likely determine control of the next Congress.

PennLive Opinion contributor Charlie Gerow is the CEO of Quantum Communications in Harrisburg. His "Donkeys & Elephants" column appears weekly opposite progressive commentator Kirstin Snow.

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