In a move characteristic of the fiercely independent Republican senator, Rand Paul of Kentucky crossed party lines Tuesday to endorse Gary Johnson, the Libertarian Party candidate for Senate in New Mexico, even though there is a Republican running in the race.

Reason Magazine called Rand Paul's endorsement, "a surprising move that could have dramatic impact on third-party politics and Capitol Hill's balance of power."

The Hill reports that Mick Rich, the Republican Senate candidate in New Mexico has faced pressure from Johnson's supporters to drop out of the race against incumbent Democratic Senator Martin Heinrich. Rich is a commercial construction contractor and newcomer to politics. Tuesday was the last day a candidate could remove their name from the general election ballot.

In the only poll that's been conducted since Gary Johnson threw his hat into the race two weeks ago, New Mexico's former governor was far ahead of the Republican– 21 percent to 11 percent (with Heinrich at 39), and Johnson even did slightly better than Rich among registered Republicans.

In an email blast Tuesday, Rand Paul told supporters:

"I have an important announcement today. I'm endorsing Gary Johnson for US Senate... He will be an important ally and a critical independent voice."

One can imagine Gary Johnson (L-NM) and Rand Paul (R-KY) tagging each other in and out of the ring for days long filibusters, a parliamentary tactic Paul has not shied away from using since winning his first election in 2010 to draw media attention to his causes and force the Republican Party to reckon with issues like the expanding role of the police state in the Obama-Trump era.

Paul notes of Johnson:

"His leadership on issues of government overreach, protecting Americans’ Fourth Amendment rights against mass surveillance, and common sense foreign policy is sorely needed in the United States Senate, for New Mexico and the nation."

High among Paul's priorities since becoming Senator has been cutting federal spending and paying down the $21 trillion national debt. During debates over the Republican tax reform plan last year, Rand Paul eschewed "revenue neutral" budgeting in favor of cutting federal revenue enough to give taxpayers some room to breathe.

In his announcement, Senator Rand Paul praised Gary Johnson's remarkable record of fiscal conservatism during his two terms as Governor of New Mexico:

"Gary Johnson is a true fiscal conservative. As Governor, he reduced the size of government while improving services. He cut taxes, and he set what may be a record by vetoing more than 700 unnecessary pieces of legislation."

It certainly was a record. In fact, Gary Johnson has pointed out that during his eight years as governor, those 700 vetoes constituted more vetoes than the vetoes of the governors of all 49 other states over the same period combined. He also reduced the government's payrolls by 1,000 employees through managed attrition without terminating anyone. By the end of his tenure, Johnson had balanced the state's budget and created a $1 billion surplus.

Though they may have a lot in common, Rand Paul's endorsement was certainly unusual in a time when party leaders are expected to march in lockstep with their party's candidates.