Sorry, Democrats. Don’t get your hopes up.

Recent poll results have some on the left believing that Democrats still have a shot at keeping control of the Senate and perhaps even the House. But that glimmer of hope is very faint.

The case for Democratic optimism goes something like this: Yes, President Biden is deeply unpopular – more unpopular at this point in his presidency than any other president since Harry Truman, according to FiveThirtyEight. Despite that, the Democratic Party’s numbers in the generic congressional ballot, which asks respondents which party’s candidates they would back if the election were held today, are higher than Biden’s approval rating. Plus, many voters who are unhappy with Biden are also uncommitted in congressional races. That gives Democrats the chance, according to this view, to convince these voters that Democrats deserve another chance to govern despite their record over the past two years.

Perhaps, but the history of undecided voters suggests that’s not likely. A late June Politico-Morning Consult poll shows that Biden had a net minus 12% job approval rating – 43% approved versus 55% who disapproved – while Democrats were ahead in the generic congressional ballot 45 to 42. That difference is largely due to two factors: Democrats who are unhappy with Biden who nevertheless support their party, and independents unhappy with Biden who are undecided for Congress. Only 79% of Democrats approve of Biden’s job performance, but 93% will vote for the party. Meanwhile a whopping 38% of independents are still undecided for Congress, even though 66% do not approve of Biden’s performance. The voters Democrats need to convince are not unhappy partisans; they are people with no party loyalties whatsoever.

These findings are replicated in virtually every other recent poll that publishes similar data. The most recent Economist-YouGov poll, for example, shows Biden underwater among independents by a 28-to-58 margin, while Democrats lead among them by only 34 to 32. The independents who are undecided, we can infer, are nearly uniformly unhappy with the president. The most recent NPRMarist and Monmouth polls also show that the undecided vote comes almost entirely from independents who disapprove of Biden.

History shows that these voters tend to break sharply against the president’s party by Election Day. The exit polls from the last four midterm elections all show that independents voted against the president’s party by between 12 and 19 points. In each case, the president had a net negative job rating on Election Day. Is there any reason, given the sharply negative views people hold toward Biden and about the state of affairs in the United States today, to think this time will be different?

Then there’s the question of sample bias. A poll’s results are only as good as its ability to accurately reflect the demographic characteristics of the voting population. Each of the four midterm polls listed above has a sample in which Democrats outnumber Republicans by between four and 6.5 points. But the largest advantage the Democrats have in the last four midterms, according to exit polls, was four points, and that was in the Democratic wave year of 2018. Democrats only outnumbered Republicans by two points in the Democratic landslide of 2006, and Republicans either tied Democrats or led by one point in the GOP landslide years of 2010 and 2014. Democrats would be defying history if they were to significantly outnumber Republicans at the polls as their party leader dredged to such depths on unpopularity.

Election prognostication this far off is a bit like weather forecasting: What appears to be a major storm could fizzle out as the front moves closer. But right now, it looks like a Category 5 political hurricane is taking form offshore. And it’s headed right toward Democratic central.