Austin Petersen, the third-place finisher for the 2016 Libertarian Party presidential nomination, is running for the U.S. Senate seat in Missouri currently held by Democrat Claire McCaskill. But he's running as a Republican and explains his decision below. For an exclusive, in-depth interview and podcast with Petersen, who also worked as a producer on Judge Andrew Napolitano's Fox Business show, Freedom Watch, go here.

Dear friends in the Libertarian Party,

For the last eight weeks, I've spent six hours a day calling my supporters to ask them their thoughts on how I might best advance liberty. I took the time to listen to every single persons' opinion about a potential opportunity to seek a seat in the U.S. Senate here in my home state of Missouri.

Of the thousands of people I spoke to, all encouraged a run, hundreds donated, and the vast majority offered their opinion regarding which party I should align with. Over 98% of them, including registered Libertarians, independents, Republicans, and even Democrats, said to run GOP.

For that reason and others, I have chosen to listen to them, as they are the lifeblood of all efforts that I will make to advance our common cause. They are the people whose time, energy, and money I will need to bring our movement a victory that we desperately need. Without the grassroots, I am incapable of action on the field. I feel I must act as a good representative and steward of their hopes and dreams for a better future.

I have served the Libertarian Party in nearly every capacity, at every level, from your humble volunteer coordinator at your national office, to one of your top contenders for President of the United States. Any future successes I may garner in the realm of politics will come in large part because of the experience and opportunities you gave me to advance American freedom, and for that I thank you.

Sadly, I must depart for now. I go with no ill will, and wish you all the best in your future endeavors.

Best Wishes,

Austin Petersen