Lots of Republicans are looking for a sane alternative to Donald Trump and Hillary Clinton, and it looks like the Libertarian Party has just given it to them, now that former Massachusetts Gov. William Weld has joined former New Mexico governor Gary Johnson’s ticket.

It’s the first time two governors have shared a presidential ticket since Republicans Thomas E. Dewey of New York and Earl Warren of California narrowly lost to incumbent President Harry Truman in 1948.

Many observers think experience as a governor is the best preparation for the job of president. Johnson and Weld would bring 14 years of gubernatorial experience to the White House, while neither Trump nor Clinton has ever served as governor or even mayor.

Johnson and Weld were both elected and re-elected in Democratic states, and dealt with heavily Democratic legislatures.

Neither Johnson nor Weld is a purist libertarian, and both have come under fire within the Libertarian Party, which will nominate its candidates in Orlando over Memorial Day weekend. Johnson displeased many libertarians (including me) by saying that government should ban discrimination on the basis of religion, including requiring a Christian baker to bake and decorate a cake for a same-sex wedding. Weld has supported some gun control measures.

But they will present a clear alternative to Trump and Clinton: strong and coherent fiscal conservatism, social liberalism, drug-policy reform, criminal-justice reform, reining in mass surveillance, ending executive abuse of power, and a prudent foreign policy that is neither promiscuously interventionist nor erratic and bombastic — all grounded in a philosophical commitment to liberty and limited government.

They acted on those ideas as governors, with the usual accommodations to political reality. Johnson was called “America’s boldest governor” by the Economist for his push for school choice. And that was before he came out for legalizing marijuana and moving away from the war on drugs. He vetoed more than 700 spending and regulation bills and left the state with a $1 billion surplus. Weld cut taxes, constrained state spending, and created a domestic partners program for gay state employees.

In the Cato Institute’s biennial Fiscal Policy Report Card on America’s Governors, both Johnson and Weld earned A’s and B’s each time they were graded. Cato’s fiscal policy analysts are tough graders, and very few governors ever get an A.

Leading Republicans such as Mitt Romney and Sen. Ben Sasse of Nebraska have declared Donald Trump unfit for the presidency and called for an alternative independent or third-party candidate to run for president. No one has stepped forward, and ballot deadlines are looming.

But now there’s an alternative they could support.

Libertarians are not conservatives. They’re not just Republicans repulsed by Trump’s racial and religious scapegoating and megalomania. The Libertarian Party platform has supported drug legalization and gay marriage for decades, and the party opposes most U.S. wars. But given what Sasse, Romney and other serious Republicans think of Trump and Clinton, is it hard to imagine that they would prefer Johnson and Weld in the White House?

The same might well be true of Sen. Dean Heller of Nevada, Gov. Charlie Baker of Massachusetts, a protégé of Weld, as well as former governors Tom Ridge of Pennsylvania and Christie Todd Whitman of New Jersey and former senators Norm Coleman of Minnesota, Tom Coburn of Oklahoma and Mel Martinez of Florida.

None of this means there’s a real path to the White House for Johnson and Weld. I suspect that in their fantasies, Libertarian party strategists imagine the Johnson-Weld ticket carrying Johnson’s New Mexico, Romney’s Utah and maybe libertarian-leaning states such as Alaska, Idaho, and New Hampshire. Add in Maine, where Weld is well known and voters have elected independents as governor and senator, and you could imagine the race being thrown into the House of Representatives. Where rational Republicans just might prefer an experienced governor to the unpredictable and threatening Trump.

But neither Johnson nor Weld is a celebrity on the order of Trump or Ross Perot, the businessman who got 19 percent of the national vote running as an independent in 1992. Neither has the money of Perot, the Koch brothers, or Tom Steyer — the kind of money that can buy national television ads and large staffs. Johnson has not yet shown an ability to draw huge crowds, as Bernie Sanders has this year and Ron Paul did in 2008.

Without those things, you can’t become a serious candidate. Johnson has already hit 10 percent in a couple of polls, but right now that’s probably a “none of the above” vote. He still has to convert it into actual support.

The Libertarian Party’s most successful campaign, in 1980, featured an accomplished and articulate candidate, a relatively large and professional staff, and a vice presidential candidate, David Koch, who put millions of dollars into the campaign. And they still only got 1 percent. Johnson and Weld have a steep hill to climb.

But Trump and Clinton are the least popular major-party nominees in memory. In some polls a majority of voters say they’d like to vote for someone else. That’s the golden opportunity awaiting some alternative candidate, and it looks increasingly as if Gary Johnson will be the only alternative on all 50 ballots.

David Boaz a native of Kentucky, is executive vice president of the Cato Institute and author of “The Libertarian Mind.”