A new poll released by WTHR/Howey Politics Indiana on Friday has Republican presidential nominee Donald Trump with a strong lead in the state over Democrat Hillary Clinton, besting her 43 percent to 36 percent.

But the poll is somewhat surprising because Trump’s polling position in Indiana has actually dropped since Gov. Mike Pence joined his ticket. An April poll by the same group before the May 3 primary had Trump beating Clinton 47 percent to 39 percent in Indiana.

Pence joined Trump’s ticket in mid-July. Trump won Indiana's pivotal primary race, effectively clinching his ability to take the nomination.

One possible reason for the polling shift is Libertarian Gary Johnson’s relatively strong support in Indiana. He got 11 percent of the support in the poll. That could change if he doesn’t make the presidential debates.

“Which way those Johnson numbers go will be pivotal,” Public Opinion Strategies pollster Gene Ulm told Howey Politics Indiana. Ulm told Howey that Johnson voters are hurting Clinton’s support here.

Of those who support Trump in Indiana, 33 percent said they would definitely vote for him. Ten percent said they would probably vote for him. Trump’s favorability rating among Hoosiers is 42 percent, while 54 percent are unfavorable toward him.

Twenty-six percent of Clinton supporters said they would definitely vote for her, while 10 percent said they probably would. Thirty-four percent of Hoosiers are favorable toward Clinton, compared with 62 percent who view her unfavorably.

Six percent of Indiana voters are still undecided. Three percent will not vote in the presidential race. And 1 percent will vote for someone else.

The WTHR/HPI poll surveyed 600 likely voters Sept. 6-8. That included 360 land line users and 240 cell phone users. The margin of error is 4 percent. The sample contained 40 percent independents, 31 percent Republicans and 28 percent Democrats.