The report that Rand Paul is interested in running for president in 2016 fetched up on the Drudge Report just as we were sitting down to write an editorial in respect of whether the neo-conservatives can find common ground with the libertarians. It strikes us as an important question. It was put into sharp relief in the past few days by Commentary magazine, whose managing editor, Jonathan Tobin, one of the journalists to watch in the rising generation, has drawn the senator into an illuminating exchange on Israel.

Mr. Tobin started things off with a dispatch issued November 9 under a headline asking “Will Rand Paul Hijack the Pro-Israel GOP?” It concluded that Senator Paul “will be far more of a force in the Republican Party in the coming years than his father ever was” and reckoned “[t]hat’s a problem for conservatives who hope the GOP remains a bulwark of common sense about national defense and foreign policy. It will also mean that one of the party’s most prominent spokesmen will not be someone who will be viewed as reliably pro-Israel.”

Dr. Paul turned around and sent Commentary a reply full of protestations of support and friendship toward the Jewish state. “Israel has long been, and will continue to be, one of our greatest allies,” says this alleged adversary of Israel. “I will always fight to maintain the health and strength of this relationship . . .” The senator’s beef with American policy toward Israel turns out to be that we are too often telling Israel what to do. That’s a sentiment that we share down to the ground, particularly when it comes to America trying to dictate settlement policy and nudging Israel to be more forthcoming in negotiations with her — and our — enemies.

The senator called foreign aid “another example of how our meddling often hurts more than its helps.” That’s also a sentiment we share. We view foreign aid as — to use the phrase the Forward used in 1991 — “Israel’s poison,” in that it underwrites statist government and retards the development of a free-market economy. America is largely out of the business of economic aid to Israel, and if Washington cuts back on aid more generally, our estimate — and Senator Paul’s — is that it will starve Israel’s enemies more than Israel.

Earlier this year a Web site called World of Judaica published in two parts what it called a thought experiment speculating about how Israel would have fared under a Ron Paul presidency. It started with 1948, when it figures “President Paul” would have let Congress be the one to recognize Israel and then set up his embassy in whatever capital Israel wanted. Our own columns have dealt with that issue in “Ron Paul’s Jerusalem.” The World of Judaica piece is a devastating reprise of the way actual American policies have dealt a worse hand to Israel than those that would have followed logically from a libertarian world view.

Now, we confess that we don’t know what is in the heart of either Ron Paul or Rand Paul, or any other politician. We do know that we are less concerned with private prejudice than public acts. We learned this with Harry Truman, who ranted against Jews and African Americans in his private correspondence yet turned out to be one of America’s greatest civil rights presidents and a friend of the Jewish state. We know that both Pauls have criticized the Civil Rights Act that we support. We addressed this in an editorial called “Heart of Atlanta.” We believe their error there is not racism but a point of law.

We also know that the Left in America is in no position to lecture any politician on anti-Semitism or anti-Zionism. The Left has been infected with both for more than a century, and the bien pensant leftists are all too quick to excuse it, whether it comes from the Reverend Jeremiah Wright or Fidel Castro. We have never accused President Obama of anti-Semitism. But speaking as a newspaper that has labored joyfully in the neo-conservative camp, we would rather have Rand Paul explicating George Washington’s farewell address than President Obama delivering the speech he did at Cairo.

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What we want in the coming contest is a campaign on the Constitution. That’s what the Sun wants. We believe the path forward is going to be found in the foundational architecture of this country — the written, plain-language text of the Constitution; enumerated, limited, and separated powers; a federal system that reserves un-delegated powers to the states and to the people; and a system that protects our rights by limiting the ability of the government to abridge them. Rand Paul is one of the politicians who have risen to power on these issues. There are others, indeed a raft of smart Republicans rising from the next generation — Mike Lee of Utah, Ted Cruz of Texas, Marco Rubio of Florida, Deb Fischer of Nebraska, Kelly Ayotte of New Hampshire, Scott Walker and Paul Ryan of Wisconsin, John Kasich of Ohio, John Thune of South Dakota, Jeb Bush of Florida, Sarah Palin of Alaska, and Chris Christie of New Jersey. We name but a few. It is a diverse field that would be but enriched and enlivened by the contribution that Rand Paul is likely to make in the coming campaigns.