Freight traffic/shipments don't lie: https://www.zerohedge.com/news/2019-07-16/recession-looms-cass-freight-index-negative-7th-month
Do you think the pullback is related to the uncertainty of the upcoming election cycle?
I think the pullback in freight/shipping is due to a slowing economy that's late in the business/economic cycle. I don't think it has anything to do with elections/Trump.
Despite what politicians and central bankers say, neither of them can cause a business/economic cycle not to end and to just "keep an expansion going" forever and avoid recessions. They can't totally prevent or halt stock market sell-offs all that easily either.
Trump came into office and inheritred an overvalued stock market and an economy that's late in its expansionary cycle. He's not likely going to be able to prevent the next contraction economically and it won't be his fault as much as it will be just the course of how economic contractions follow economic expansions...and we've been in an economic expansion WAY longer than what's typical. It also makes people and investors numb to the idea of an economic contraction because all they've known is an economic expansion for so long.