Craig Gilbert

Milwaukee Journal Sentinel

At double-digits in the polls, Libertarian Gary Johnson could easily affect the outcome in Wisconsin in the event of a very close presidential race.

But Johnson is drawing support right now from groups on both sides of the partisan divide, making it hard to predict which candidate will be hurt more by his presence on the ballot next month — Democrat Hillary Clinton or Republican Donald Trump.

Johnson had the support of 11% of likely voters in a Wisconsin poll taken Sept. 15-18 by the Marquette University Law School, leaving him far behind Clinton (41%) and Trump (38%).

Who are the Johnson voters in Wisconsin?

They lean male and Republican, which suggests Johnson may be taking some votes away from Trump.

But they also skew young and secular and moderate, which suggests he’s taking some votes away from Clinton, too.

Johnson’s overall support has grown modestly in Wisconsin from 8% of likely voters in July to 9% in early August to 10% in late August to 11% in mid-September, according to Marquette’s polling

That support is much higher among some groups than it is among others.

For example, Johnson, the former governor of New Mexico, is getting 19% among independents. He is doing especially well among independents who lean Republican — 22%.

Johnson has considerably more support among men (14%) than women (8%).

He is winning 18% of voters under 45 but only 4% of voters 60 and older.

He gets more support from people who never go to church (14%) than from people who attend church at least weekly (8%).

There is also a regional tilt to his coalition in Wisconsin. Johnson does very poorly (5%) in Milwaukee, which is heavily Democratic and has a large African-American vote.

But he does far better in the state’s other Democratic bastion, Dane County, whose population is much whiter than Milwaukee’s.

In fact, at 17%, Johnson is running second in Dane County in Marquette’s polling in recent months — far behind Clinton (she’s at 57%) but narrowly ahead of Trump, who is drawing a meager 15% in that big blue county. (Jill Stein of the Green Party is only at 5% in Dane).

All these numbers are based on the last three statewide surveys conducted by Marquette pollster Charles Franklin (two in August and one in September), in which a combined 2,410 registered voters in Wisconsin were interviewed.

Franklin says his polling suggests Johnson is cutting into each party’s coalition, a pattern that has surfaced in other states, as well.

“I think the evidence at the moment suggests he’s hurting both equally, but there is nothing to say for sure that’s how it will end up,” said Boston-based pollster (and Wisconsin native) Steve Koczela, who just conducted a poll in New Hampshire that showed Johnson at 13% in that battleground state.

Johnson’s support in New Hampshire looks a lot like his support in Wisconsin: he wins 24% of independent men, 15% of Republican men, but only 4% of Democratic women; he’s at 27% with voters under 30, but just 4% with voters 60 and older.

“It’s remarkable how much support Gary Johnson seems to be taking from both sides,” Koczela said. He notes that a Libertarian on the ballot would normally be expected to hurt the Republican candidate more than the Democrat.

But in this case, “he’s drawing equally from both, and in many polls, drawing slightly more from Clinton,” he said.

Some analysts expect the Johnson vote to decline as the election nears, because third-party candidates often follow that pattern. That has not yet happened in the Wisconsin polling.

Johnson has drawn some embarrassing blanks on foreign policy in recent interviews, which could hurt him. And his absence from the debates could cost him support. But at the same time, he has picked up some major newspaper endorsements and continues to benefit from the unpopularity of Trump and Clinton.

Where might his voters go if they turn away from Johnson?

Some of them will probably not vote. Johnson supporters in Wisconsin are less likely than Trump and Clinton supporters to follow politics closely and less likely to say they’re certain to go to the polls next month.

Philosophically, a majority (54%) of the Johnson voters are self-described moderates, and most aren’t frequent church-goers. Those are qualities they share more with Clinton voters than Trump voters.

But a majority (55%) are either Republican or GOP-leaning independents, and six in 10 are men — qualities they share more with Trump voters.