The collapse of Democrats’ popularity on the much-ballyhooed generic ballot foreshadows tough midterm elections for them in November.

Until this week, pundits nearly everywhere favored Democrats to win – and for good reason. Historically, midterm election victories have been afforded to the party that does not control the White House. That’s a natural result of the checks and balances established by our Founding Fathers.

Generic ballot polling is generally thought to be the best predictor of the mood of the electorate during a midterm season. Such polls usually ask the question: “If the election were held today, would you vote for a Democrat or Republican for Congress?”

The latest responses are very troubling for Democrats.

New polling shows that Democrats have lost their recent 15-point lead over Republicans, dropping to only a two-point lead for a critical election they had hoped to paint as a referendum on President Trump and writ large, Republicans.

However, historically speaking, the news is more daunting for Democrats. Compared to where they stood in the 2014 midterm elections , Democrats are actually faring worse at this point than they were then.

In the 2014 midterms, Democrats were ahead on the generic ballot by an impressive eight points most of the year. However their lead eventually vanished, and Republicans ultimately trounced them at the ballot box, retook the U.S. Senate and won a big majority of seats in the House of Representatives.

By comparison, Democrats’ current poll numbers also rate worse than their generic ballot ranking in the 2010 midterms.

In the 2010 contest, Democrats were ahead of Republicans by a whopping 12 points heading into the midterm year. However, Republicans pulled ahead slightly in February 2010 , only to cede ground to Democrats in the summer months. Ultimately, Republicans ended up winning back control of the House and taking back the gavel from then-Speaker Nancy Pelosi, D-Calif.

Compare the 2010 and 2014 figures to the paltry two-point advantage that Democrats have on Republicans today, and the 2018 midterms become very interesting to watch.

But wait, there’s more bad news for Democrats. The narrow lead they now hold may be overblown due to bias in the polls.

Five Thirty Eight’s Nate Silver explained a couple of years ago that Democrats blew their lead in 2014 even though the generic ballot polling was prejudiced nearly four points in their favor. In fact, Silver found that 2010 midterm generic ballot polling was skewed in favor of Democrats as well, with much the same result (they lost).

So one has to presume that the same polls, run by the same mainstream media outlets, remain skewed, especially considering how badly the polls underestimated support for Donald Trump and missed the mark in 2016.

Therefore, if Democrats are only two points ahead on the generic ballot and if Silver’s assessment of a four-point skew in favor of Democrats is accurate (and it was in 2014), it’s fair to suggest that Republicans are actually up by two points.

Whether the polls prove to be biased or not in November remains to be seen. But Democrats ought to be concerned that their support fell by 13 points in just one month.

The reason for Democrats’ plummeting popularity can be attributed to a few key events during that 30-day period:

First, by passing the American Tax Cuts and Jobs Act , Republicans in Congress not only delivered on their promise of tax cuts for the American people, they ignited a wave of bonuses and pay hikes for 3 million American workers thus far (spoiler alert: many more announcements are expected soon.)

Second, Republicans won the government shutdown fight when they quickly coined the term #SchumerShutdown, exposing Senate Minority Leader Chuck Schumer of New York and his fellow Democrats as they attempted to further use DACA “Dreamers” as pawns in an unrelated budget deal.

Third, Republicans no doubt experienced a “Trump bump” after President Trump impressed the nation with a heartfelt State of the Union address. Using a tapestry of personal stories from heroes, victim’s families and survivors, the president did what he does best – he sold American exceptionalism.

Americans watched as President Trump’s poll numbers jumped a stunning 10 points while Democrats sat on their hands.

The rise in popularity for President Trump is undoubtedly a negative development for Democrats in the zero-sum game of politics. As the president’s popularity increases among American voters, Democrats have less to rail against.

With a 17-year high in consumer confidence, 17-year low in unemployment (along with the lowest African-American unemployment rate since measurements began in 1972), a 17-year low in illegal border crossings, the fastest return of manufacturing jobs in 13 years, and so much more, American voters are taking note. Democrats have a tough challenge to find something concrete upon which to critique this president, other than simply his brash style.

While the new generic ballot polling numbers don’t guarantee a Republican win, the factors discussed above do not bode well for Democrats.