The libertarian-leaning senator also discusses his long, uphill fight to get U.S. troops out of Afghanistan.

The three most libertarian members of Congress are, unsurprisingly, good friends and allies. Sen. Rand Paul (R–Ky.), Rep. Thomas Massie (R–Ky.), and Rep. Justin Amash (R–Mich.) team up constantly on often-lonely crusades to restrain federal spending, rehabilitate constitutional governance, and remove U.S. troops from far-flung conflicts.

The two congressmen were loyal footsoldiers in the senator's star-crossed run at the 2016 GOP presidential nomination. (Massie's story about canvassing for Paul in Iowa is one of the most colorful explainers for how the Tea Party movement mutated into Trumpism.) In 2020, Paul is firmly on the sidelines, as is Massie ("I am absolutely ruling out a run for any office in 2020 as a big-L Libertarian," the congressman told me last summer), which leaves Amash, who is currently weighing his third-party options.

Paul last fall took the unusual step of endorsing Libertarian candidate Gary Johnson in his New Mexico Senate race against the eventually victorious Democratic incumbent Martin Heinrich and the GOP political newbie Mick Rich, despite the arm's-length relationship over the years between Johnson and the Paul family. So when I interviewed the senator about Afghanistan on Sirius XM Insight's Stand UP! with Pete Dominick Wednesday, I asked whether he would encourage Amash to run and/or consider supporting an Amash campaign.

"Well, you know, it's sort of a weird thing," Paul began. "My dad was a Libertarian candidate in 1988, and I supported him, but it has been difficult, because through the years there hasn't been enough momentum gained to show electoral progress. So, like, in some Senate races, I've actually tried to discourage the Libertarian, because I think they draw enough votes from the Republican, who often is a libertarian. We had a race in Virginia not too long ago where I thought the Republican was more libertarian than the Libertarian, who wanted…[to] raise the gas tax and put GPSs on everybody's car to monitor their driving, which didn't sound very libertarian.