Apple's blockbuster announcement that it will repatriate almost all of its $250 billion in overseas cash, create 20,000 new U.S. jobs, open a new U.S. campus, and add $350 billion to the U.S. economy ends any serious debate about the new tax reform law.

The fact is, it's a big net positive for America even if only a portion of Apple's announcement is directly attributable to the tax law. Choosing to argue otherwise is a case of overwrought obstinacy.

So does this mean a big turnaround for President Donald Trump and the Republicans in the polls? Is the predicted "blue wave" in the 2018 midterm elections less of a sure thing now?

Not so fast.

A strong economy is usually the biggest factor in U.S. elections. But that needs to be balanced with another truth best articulated by the late Speaker of the House Tip O'Neill who wisely said, "All politics is local."

Big macroeconomic news, no matter how good, doesn't necessarily translate into votes until enough voters on Main Street feel the positive effects. Therein lies the challenge for the Trump team and the GOP Congress. They need to find a way to bring these big economic stories home to voters and fast.

The key to meeting that challenge relies on two factors: Trump being Trump and Democrats being Democrats.

First, let's look at Trump being Trump. Financial news organizations such as CNBC might make a big deal out of the Apple announcement and this historic stock rally, but that kind of positive economic news often struggles to see the light of day in most of the mainstream news media.

Enter Trump and his amazing Twitter machine! Not a day seems to go by without the president tweeting out the good economic news to his 47 million followers.

One of his tweets earlier this week focused on the Main Street part of the equation:

But it isn't just Twitter. Trump has shown an unusual fervor to get out of the White House and barnstorm the country when it comes to the economy and taxes.

While he made few public appearances specifically tied to the effort to repeal Obamacare, he began showing up at factories and job sites to publicize his claimed positive effect on hiring and the economy even before he took the oath of office.

When the tax reform bill was being debated in Congress, Trump made campaign-style appearances across the country pushing hard for the plan. The events were so well-attended that even some Democrats who didn't end up voting for the tax reform bill felt compelled to appear with the president at them.

But Trump clearly knows that getting the bill passed was just half the battle. He's continuing the tour touting tax reform even this week as he travels to the crucial swing state of Pennsylvania to talk up the economy at a manufacturing plant and support Republican candidate Rick Saccone in a House special election outside Pittsburgh.

That's precisely the kind of event that Democrats should fear.

But the Democrats could also make another contribution toward ruining their own midterm advantages. So far, most Democrats are either trying to throw cold water on the positive economic news or they're focusing on Trump-related distractions, from the president's health to his vulgar comments about immigration.

In that effort, perhaps they've only succeeded in distracting themselves. Their double-digit leads in generic ballot midterm polls are already starting to noticeably fade in some key surveys. A hedge-fund manager friend of mine who is no fan of Trump emailed me Wednesday fuming that Democrats are making fools of themselves by denying the positives of the new tax law. He predicts they will be doomed if they don't find a way to acknowledge reality.

They're running out of time to do it, because phase two of changes from the new tax law hits in just a few weeks,

when workers across the country are expected to see a noticeable increase in their paychecks.

If Trump finds the time to tweet and comment regularly about that on payday Fridays, the Democrats will have a big problem on their hands by November. Anybody want to bet he won't?

The Democrats shouldn't make that bet. But neither should the Republicans in Congress bet on Trump being able to do all the heavy lifting by himself. No matter how much his bluster and crass self-promotion may annoy them, following his lead and boldly talking up the economy and taking credit for it is their best chance to save their jobs in Washington.

Commentary by Jake Novak, CNBC.com senior columnist. Follow him on Twitter @jakejakeny.

For more insight from CNBC contributors, follow @CNBCopinion on Twitter.