Trump vs. McConnell: Here’s where this crazy feud is headed

• President Trump and Senate Majority Leader Mitch McConnell are currently in what the New York Times is calling a "political cold war."
• McConnell clearly has the most to lose—if the tides turn and the GOP loses the majority in the midterm elections, he loses his leadership position.
• However, both Trump and McConnell would be wise to focus on getting something done—specifically on tax reform and foreign policy in areas like Afghanistan.

President Donald Trump and Senate Majority Leader Mitch McConnell are apparently no longer on speaking terms, with the New York Times going so far as to call it a "political cold war."

Trump has gone after McConnell for everything from the failed Obamacare repeal effort to not doing enough to protect the president from the Russian investigation. McConnell, meanwhile, has apparently been privately telling some colleagues that he questions whether President Trump will last through his entire term.

First, the president and Congress don't have time to feud. After a series of setbacks this year, they need to focus on getting things done — not bickering with each other.

The one who has the most to lose in all of this is McConnell. Think about it: The next presidential election isn't until 2020. And, while McConnell doesn't face re-election for his Senate seat until 2020 as well, the congressional mid-terms for other seats are coming up in 2018 and if the Republicans lose control of the Senate, McConnell loses his power as majority leader.

And, there's nothing to say his leadership position is safe until 2018. Senate majority leaders are elected by the majority party only and, while McConnell has a clear majority of GOP senators on his side, even those walls protecting a sitting leader can come down fast. Just ask former Senate Majority Leader Trent Lott. Lott was never voted out, he simply stepped down as leader in 2002 when he faced so much personal scrutiny in the news media.

A new poll shows that only 18 percent of voters in McConnell's own home state of Kentucky approve of the job he's doing in the Senate. 18 percent! If those poll numbers don't improve, and Trump supporters nationwide get louder in their calls for his ouster, McConnell could face the same kind of pressure that sank Lott.

With that in mind, don't believe for a second that McConnell is foolish enough to take this feud so far that it derails the general GOP legislative agenda just because achieving some parts of that agenda will also help President Trump. McConnell needs to avoid a circular firing squad.

And that makes the discussion all about tax reform right now. McConnell and President Trump both need it to happen and happen before we get too close to those 2018 midterms. That fact is becoming increasingly clear to many insiders and even investors who now seem to see the chances improving of at least some tax cuts getting passed. That optimism fueled Tuesday's big rally on Wall Street.

And tax reform isn't the only joint goal. President Trump's recent moves on foreign policy, from taking a hard line on North Korea to adjusting U.S. policy in Afghanistan, are positions Republicans can support, too. In fact, House Speaker Paul Ryan and frequent Trump critic Senator Lindsay Graham were very quick to endorse President Trump's speech on Afghanistan Monday night.

Ryan might be acting like a team player right now because he's more forgiving in nature. Though, it's more likely that his decision is based on simple math. Remember, the entire House is up for re-election next year, while only eight Republican Senators face re-election in 2018. The chances that Ryan could lose his speaker's job simply from the election results are real and more dangerous than what McConnell is facing. Thus, Ryan has a bigger incentive to promote a more unified front to the voters.

In fact, it's most helpful to look at all the public attacks against President Trump from sitting Republicans through that electoral lens. When Republicans not up for re-election next year like Graham and Senator John McCain blast the president, it's one thing. But it means a lot more when someone who is running next year, like Tennessee Senator Bob Corker, criticize President Trump.

In short, foreign policy and taxes are issues where there is still a way forward between the White House and Congress. And those incumbents up for re-election in 2018 have too much riding on them not to push for progress in those areas at least.

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

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

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