There’s one person who will affect Missouri’s U.S. Senate race more than a pointed attack ad or dumptrucks full of money: President Donald Trump.

Both U.S. Sen. Claire McCaskill and Attorney General Josh Hawley believe he’ll make an impact in their nationally-watched contest.

The question, though, is who will benefit?

Hawley and his Republican allies are looking for a repeat in 2016, where Trump won Missouri by a historic margin. He’s hoping that Trump still retains popularity in the state’s rural counties and socially conservative suburbs — places Hawley needs to win to defeat McCaskill.

McCaskill, though, believes Trump’s policies could motivate key Democratic strongholds — like St. Louis, Kansas City and Columbia. And she’s banking on his steel and aluminum tariffs making rural voters think twice about voting for Republicans.

While Missouri voters don’t always sway with the national environment when choosing a senator, they have in the recent past. Republican candidates won during GOP wave elections in 2002, 2010 and 2016. McCaskill first captured her Senate seat in 2006, one of the strongest years for Democratic candidates in modern history.

And most observers agree that Trump will play a big role in shaping the nation’s mood on Nov. 6.

“I think this will be a mandate on the Trump administration if Josh Hawley wins or Josh Hawley loses,” said Jefferson County Executive Ken Waller.

Rural fervor

Credit File photo I Carolina Hidalgo | St. Louis Public Radio GOP U.S. Senate hopeful Josh Hawley greets President Donald Trump at St. Louis Lambert International Airport in March.

On a typical Friday afternoon during Missouri’s frenetic election season, Hawley received a warm reception from Republican volunteers in Jefferson County. Voters here are often the bellwether in statewide contests. In 2016, Jefferson County voter gave Donald Trump 65 percent of vote. He won the rest of the state by 19 points.

So it’s no accident that Hawley included this line in his stump speech:

“Are we going to send somebody who will listen to the people of Missouri and support President Trump’s agenda — or are we going to send back to the Congress, to the Senate, Claire McCaskill who has opposed this president, knee jerk at every opportunity?” Hawley said.

From the start of his campaign, Hawley has attached himself with Trump and his administration. He’s appeared with both the president and Vice President Mike Pence at rallies. Trump is coming to Missouri again this week, visiting Cape Girardeau on Thursday with Hawley expected at his side.

And some third-party groups aligned with the GOP have used clips from Trump to attack McCaskill.

“I’m pleased to have the support of the president,” Hawley said.

It’s not just swing areas like Jefferson County where Trump’s popularity could be key. Trump won rural counties in Missouri with more than 70 percent of the vote. And Hawley needs a strong turnout there to beat McCaskill, who traditionally has done well in outstate Missouri.

Gary Leggens, a Washington County native who is part of a group called Bikers for Trump, noted that the president won the congressional district that includes Cape Girardeau with more than 70 percent of the vote.

“Our appeal for him is he’s real. He gets down to the grassroots level — and he deals with the issues that deal with us on a day-to-day basis,” said Leggens. “And he’s going throughout our state doing great things as well. Everything that he can do to make America great again.”

Storm clouds

Credit File photo | Carolina Hidalgo | St. Louis Public Radio Protesters gathered in downtown Clayton in February 2017 to show solidarity with immigrants and refugees following the announcement of President Trump's executive orders.

Public approval ratings for Missouri (with some exceptions) place Trump’s standing around 50 percent — higher than the national average. But Trump’s actions are threatening to lower that number.

For one thing, Missouri farmers are worried about how Trump’s steel and aluminum tariffs resulted in retaliation against crops. Even groups that have endorsed Hawley, such as the Missouri Farm Bureau have been concerned about the tariffs’ impact on soybeans. McCaskill has been sounding the alarm on the issue for months.

Outside of Missouri, Robert Mueller’s investigation in Russian interference in the 2016 election could bring about more embarrassing revelations. And then there’s questions about Trump’s temperament and stability, which were laid out in an anonymous New York Times op ed published last week.

Credit Carolina Hidalgo | St. Louis Public Radio Sen. Claire McCaskill speaks to reporters at Lona's Lil Eats in St. Louis on Aug. 30.

These controversies, as well as Trump’s immigration and health care policies, are motivation to Democratic activists like St. Louis 5th Ward Committeeman Rasheen Aldridge.

“I think people are fired up. And I’m optimistic because I’m young,” Aldridge said. “I’m really in good hope and faith that a lot of folks that did not get out in 2016, for whatever reasons, are going to get out now because of what’s been happening.”

If Aldridge is correct about an uptick in Democratic enthusiasm, then it could help McCaskill get the high turnout she needs in places like St. Louis and St. Louis County. It could also help her capture some suburbs that go back and forth between Republicans and Democrats — like Jefferson or Buchanan counties.

For the most part, McCaskill’s criticism of Trump is generally focusing on his policies — and not necessarily his leadership or personality style. Unlike some of her party’s base, she hasn’t called for his impeachment — and added that she was uncomfortable that the author of the New York Times op ed wrote anonymously.

“Any talk of impeachment is inappropriate until the Mueller investigation is complete,” McCaskill said.

Most of the ads that McCaskill and her allies have run against Hawley aren’t trying to use Trump as a millstone — as is the case in competitive congressional races in suburban Chicago. But McCaskill has noted to reporters that there’s “not an inch of daylight” between Trump and Hawley — a sign she may use the president’s support of her challenger against him.

“Clearly, Josh Hawley is one of President Donald Trump’s No. 1 priorities in the fall. And the more Donald Trump comes in here, I think the more it will remind people that we need to elect somebody who’s willing to be a check and not just a yes man,” McCaskill said.

Tuning out?

Credit File photo I Carolina Hidalgo | St. Louis Public Radio President Donald Trump speaks at a Granite City Works warehouse on July 26.

Hawley has dismissed the idea that Trump’s actions and controversy are resonating with Missouri voters. He contends that voters aren’t following every development surrounding his presidency.

“And I think to a lot of people, it smacks of the fact that this is just an attempt to overturn the results of the 2016 election,” Hawley said. “And I think frankly, the media ought to accept the fact the president won the 2016 election fair and square.”

GOP state House candidate Jim Murphy says voters aren’t all worried about Trump.

“For the most part, people aren’t focused on Trump,” said Murphy, who’s running for a highly-competitive seat in south St. Louis County. “They’re focused on their day-to-day. They’re focused on their jobs. They’re focused on the local issues. Are the roads going to get fixed or are we going to have a gasoline tax or are we going to have all of those things.”

Whether Trump’s standing affects this particular election remains to be seen, McCaskill said.

“We now have Donald Trump on the air with paid advertising embracing Josh Hawley and rejecting me over and over and over again,” McCaskill said. “I know he’ll be in Missouri campaigning for Josh Hawley a number of times. So it remains to be seen whether his presence in the campaign is more motivating for the base of the Republican Party or more motivating for people who think we should get back to maybe somebody who is a little more unifying in our country — and doesn’t cause such division.”

There is recent precedent where Missourians went against the winds of the national environment. McCaskill trounced Republican Todd Akin in 2012 — even though Mitt Romney won the state handily. Akin’s campaign imploded after his comments about rape and pregnancy drew a nationwide outcry.

Follow Jason on Twitter: @jrosenbaum