In a Michigan race with a potentially embattled incumbent, two pro-business groups have recently thrown support to the challenger.

This past week, Republican Justin Amash's challenger, Brian Ellis, received the endorsements of the Michigan Chamber of Commerce and the Michigan Farm Bureau. However, this came after the news that Justin Amash leads in a new poll.

In its endorsement, a senior vice president of the Chamber of Commerce said:

"Brian Ellis' 30-year business career includes running his own financial advisory firm and serving as president of his own food processing business that employed over 200 people."

Another VP said, "We can trust Brian Ellis to support and vote for policies that promote America's free-enterprise system."

In accepting these endorsements, Ellis said:

"I think these entities see me in a 30-year career in business and know about pro-growth policies . . . that Justin hasn't supported. The approach of Justin Amash of just saying 'no' is not a solution to solve anything."

Many businesses in the district and throughout the state appear to be amassing around Ellis. However, Amash continues to get support from at least one wealthy family in the district, the DeVos, which includes a former president of Amway.

In his campaign, Ellis has criticized Amash's vote against a balanced budget amendment and a present against the Keystone XL pipeline. He has also made a point of some alleged inconsistencies on Amash's abortion stance, which has previously cost the congressman the support of the Michigan Right to Life Committee.

In defending his opposition to the Keystone XL Pipeline and in certain abortion-related legislation, Amash has explained that he votes present when the bills single out a particular company or entity.

The charges against Amash of ideological heresy are not new. He was called the "most liberal Republican" by political strategist Karl Rove, in part because Amash frequently votes against his party.

Still, according to OpenCongress.org, Amash votes with Republicans approximately 80 percent of the time. Plus, he has received perfect scores from the Club for Growth, the Cato Institute, and the National Right to Life Committee.

A recent poll conducted by Michigan Information and Research Service (MIRS), an independent firm, found Amash leading Ellis 42-23, with 35 percent of participants undecided. Six thousand likely Republican primary voters were called and 472 responded.

Donald Zinman, a political science professor at Grand Valley State University, believes "Amash might have the upper hand" because primaries typically bring out the most enthusiastic supporters. With so much time left before voting, Zinman also said the 19-point lead was significant, although "if he had a 20-point lead the weekend before the election, it'd be all over."

Amash, who recently set a record alongside Arkansas Rep. Steve Womack (R) for the longest streak of consecutive congressional votes cast among current representatives, is known to be tireless.

As an incumbent, Amash has several built-in advantages. As the endorsements pile up for his opponent, he will likely need voter enthusiasm to successfully fend off this challenge. However, since Justin Amash leads in a new poll, the electoral momentum still appears to be with him.