Anthony Zurcher

If you look at the results from last year's presidential election, Donald Trump won the 7th District of Tennessee, this district, by 22 percentage points, which suggests that this is a fairly reliably conservative district.

So while it's just one district and it won't determine who controls Congress, at least in the short run, it could have a lot of significance for how this country is feeling.

That's why both parties are sinking resources into this, because Republicans don't want this to be a reflection on voters souring on their control of government.

I think a Republican loss would be a seismic event for Republicans.

It would be a huge warning sign that they are not safe even in what are considered to be comfortable Republican seats.

The voters are becoming increasingly dissatisfied with the incumbents.

There are indications of some cracks may be forming in Donald Trump's base.

And while this election won't shatter that base, it could be an indication that Republicans not only are starting to try to think a little bit about distancing themselves from Donald Trump, but also starting to think about what a Republican Party future looks like after Donald Trump leaves office, which will now at this point only be in a matter of just over three years.