This is #WAR: Here are the likely names on Bannon’s short list

  • Now that he's out of the White House and back at Breitbart News, Steve Bannon can really make a serious impact on the 2018 midterm elections.
  • Paul Ryan probably isn't in any immediate danger of being a Bannon target—but other Republicans are.
  • Trump critics like GOP Senators Jeff Flake and Bob Corker are probably on Bannon's short list of targets, as well as Senate Majority Leader Mitch McConnell.
  • Debbie Stabenow is the most likely Democrat on Bannon's hit list.

Now that Steve Bannon has left the White House and is back at Breitbart News, get ready for some fireworks. Or, as Breitbart Senior Editor Joel Pollak so elegantly tweeted: #WAR.

No, Bannon's ouster does not mean he will use his news and opinion website to get revenge on the administration as many people assumed after Pollak's tweet, which came moments after the Bannon departure was reported:

The #WAR will likely involve the targets Bannon and Breitbart were already hitting before the Trump campaign even started: Democrats, the mainstream news media, and establishment Republicans. Or as Breitbart followers call them: "leftists, fake news promoters, and crony capitalists."

But with its readership solidly already on the right, Breitbart likely won't make any dents against most Democrats and newspapers like the New York Times that it wouldn't have already without Bannon back at the helm. It's the third part of that usual suspects target list, establishment Republicans, who are in real trouble.

That is, the GOP members of Congress who have stood in the way of not just the Trump agenda, but the more generally conservative agenda over the years. Remember that it's in primaries and midterm elections where talk radio and the more niche news websites make their greatest impact. That's been an acknowledged fact since at least 1994, when the GOP took control of Congress for the first time since the 1950s, thanks in large part to conservative talk radio.

And that brings us to the heart of the matter. Sure, Bannon might publish hit pieces against administration figures like chief economic adviser Gary Cohn or even attacks on Jared Kushner and Ivanka Trump that would make the general news media and chattering classes buzz with excitement.

The real impact is what Breitbart and sites like it can do to the upcoming midterm elections in 2018. The lower turnout for those midterm general elections, and even lower turnout in midterm primaries, make it that rallying a few more readers to register and vote in a handful of states and districts can make all the difference.

With that in mind, let's look at the four incumbents in Congress who should be most concerned that Bannon is back at his internet battle station:

Jeff Flake, Republican senator from Arizona

Flake, who has become a major critic of President Trump, is up for re-election in 2018. He already faces a primary challenger in Kelli Ward, who has decent name recognition thanks to sites like Breitbart that have covered her generally favorably since she challenged Arizona's other senator, John McCain, in the 2016 GOP primary.

A recent Breitbart piece described Ward as a "populist" running against the "globalist" Flake. And for Breitbart readers, "globalist" is about as bad a title you can get. And again, Ward has been basically running for almost two years already and is hardly an unseasoned upstart.

The overall electorate in Arizona seems down on Flake, based on his 18 percent approval rating in a recent survey by Public Policy Polling. And lest you think that low rating was connected to Flake's begrudging vote in favor of the failed GOP Obamacare replacement bill, note that in the same poll, that bill got a 31 percent approval rating and President Trump clocked in at 44 percent approval.

Debbie Stabenow, Democratic senator from Michigan

President Trump's victory in Michigan in 2016 was a key cog in his overall election victory. Now, that state's Democratic U.S. Senator Debbie Stabenow faces re-election with a hefty 37 percent disapproval rating around her neck. It's that weakness in the polls and Michigan's renewed status as an unpredictable swing state that made celebrities like Kid Rock, (real name, Robert Ritchie), a viable alternative to her in some recent polls. And sure enough, Breitbart has trumpeted Kid Rock's strength in some of those polls against Stabenow in recent articles.

If Kid Rock is serious about continuing his campaign, he could get a significant shot in the arm from conservative sites like Breitbart. And she is one Democrat who could be wounded by Bannon as much as any Republican.

Bob Corker, Republican senator from Tennessee

Another more recently vociferous Trump critic is Tennessee Republican Senator Bob Corker. But he's been in Breitbart and Bannon crosshairs since 2015, when conservatives blamed him for either intentionally or ignorantly allowing President Barack Obama's nuclear deal with Iran to clear the U.S. Senate.

Unlike Flake, Corker doesn't have a real primary challenger just yet. But many conservatives want one to emerge. Mark Green, who was President Trump's original choice as Secretary of the Army, is considered one possible choice.

Mitch McConnell, Senate Majority Leader (Republican from Kentucky)

Senate Majority Leader Mitch McConnell.
Nicholas Kamm | AFP | Getty Images
Senate Majority Leader Mitch McConnell.

No, the Kentucky Republican Senator and Majority Leader isn't up for re-election in 2018. But his leadership job will be toast if conservatives who are furious with his performance manage to either successfully defeat some of his loyalists in primaries or weaken GOP Senate candidates enough to hand the body back over to the Democrats next year.

And aside from the midterms, Breitbart can easily raise the volume on its continued criticism of McConnell. In this effort, the website has powerful conservative allies like talk radio host Mark Levin. If Bannon was in any way restrained in his attacks on the establishment Republican-led Congress while he was in the White House, those restraints are off now.

And there are other potential targets to be sure, including Speaker Paul Ryan if Bannon and others decide to make similar concerted efforts in the House elections.

But Flake, Stabenow, Corker, and McConnell are the targets Bannon's already marked and hit in the past and now he has renewed reasons to go after them. Coming off a 2014 midterm election, where turnout was the lowest in 70 years, a strong effort online could get serious bang for every buck and shared article. For someone like Bannon, that's going to be too good a scenario to pass up. And those numbers might indeed make him more powerful outside of the administration than he ever was in it.

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

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

WATCH: This rhetorical 'war' is going to be fun