WASHINGTON — At 10 a.m. Tuesday, Rep. Greg Walden of Oregon, the man in charge of House Republicans’ 2014 campaign, told a roomful of reporters at the National Press Club that they shouldn’t read much into that day’s special election in Florida to fill the seat of the late GOP congressman Bill Young.

“Whether we win it or lose it, the special elections aren’t too predictive for either side going forward,” said Walden, head of the National Republican Congressional Committee.

“If there’s any advantage of a special election,” Walden added, “it’s that you can test messages, and you can test strategies, and you can test sort of your theories on voter turnout and ID. So, I mean, that’s kind of the takeaway … from a special, far more than is it indicative of what’s going to happen 239 days from now.”

But at 8 p.m., after Republican David Jolly, a former lobbyist, was declared the winner by two percentage points, Walden revised his view of the race’s significance.

“David proved that Pinellas County voters are tired of the devastating policies of this administration,” he said in a statement. “Tonight, one of Nancy Pelosi’s most prized candidates was ultimately brought down because of her unwavering support for Obamacare, and that should be a loud warning for other Democrats running coast to coast.”

Walden then hit the TV circuit Wednesday to say that after the special election — the contest he said wouldn’t be “too predictive” — Democrats should be “pretty panicked this morning.”

Democrats are indeed in a freak-out about the results in Florida, and about whether Obamacare, or President Obama, will ruin the party in the fall. But Walden was right the first time.

Democrats are likely to have a lousy midterm election — Republicans are forecast to pad their House majority by a few seats and to have a decent chance of taking control of the Senate — but this has nothing to do with what happened in Florida on Tuesday. An NBC News-Wall Street Journal survey this week found Obama’s job approval rating at a record low and an unusually high percentage of voters eager to register that dissatisfaction at the polls. But the causes of the party’s difficulties this year are larger than any issue, candidate or president, and those who are casting November’s vote as the Great Obamacare Referendum are almost certainly overdoing it.

Some perspective:

The prospect of Democrats regaining control of the House was never a real possibility. Democratic House candidates won 1.7 million more votes than Republicans in 2012, beating the GOP by a full percentage point, but they still remain 17 seats shy of the majority. Because of gerrymandered districts and population concentrations, Democrats would need to win the popular vote by seven percentage points, by some estimates, to retake the House. And this certainly isn’t going to be the year for such a landslide: The president’s party usually loses seats in a midterm election, particularly in a second term.

In the Senate, meanwhile, Republicans probably already would have 50 seats rather than their current 45 if the tea party hadn’t caused the GOP to throw away so many races in 2010 and 2012. Tea party candidates beat more electable Republican candidates in Colorado, Delaware, Indiana, Missouri and Nevada, and seats that easily could have been Republican went Democratic. A year before the 2012 election, Republicans had been forecast to win the Senate.

It’s true that the most vulnerable Democrats this year are from states where Obama and Obamacare are unpopular. But a lot of those candidates are in office now because 2008 was an uncommonly good year for Democrats. Likewise, the echo of 2010 — a good year for Republicans — should help Democrats in 2016. And long-term demographic trends, particularly the growing importance of Latino voters, strongly favor Democrats.

Democrats may well be miserable on the morning of Nov. 5, and Republicans will attribute the results to Obamacare. But they will have more to do with what Walden described Tuesday. You “have the national atmospherics” working against Obama, he said, but the outcome will be determined by the quirks of the handful of districts that are in play.

“So what issues?” Walden asked himself. “What matters to the people in that district, wherever that district is. That’s how you’re going to win a race.”

This will be worth remembering whenever there’s hyperventilating over the meaning of the midterms.

Dana Milbank is a Washington Post columnist.