His best chance of making headway in a presidential race is to leverage the trust conservatives have for him on domestic issues to make his foreign policy views easier for conservatives to accept. If it’s him debating foreign policy with the likes of New Jersey Gov. Chris Christie or other figures favored by the party’s establishment, it would be much easier for Paul to muddy the waters. He could essentially argue, “Of course, big government establishment RINOs would smear my foreign policy views, because they’re frightened of having a true conservative win.”

That’s much harder to do with Cruz in the picture. Cruz has at least as much credibility as Paul with the conservative base — if not more. Whether or not Cruz runs, having him in the media amplifying the criticism of Paul’s foreign policy views would make Paul’s already difficult job of trying to appeal to a wider electorate that much harder. He cannot dismiss Cruz as just another establishment RINO trying to sabotage the candidacy of a genuine conservative. Anything Paul does to assert that he really believes in a strong role for the U.S. in global affairs risks alienating his father’s energetic supporters, who favor a more restrained foreign policy. Anything he does to shore up support among this core group of his father’s supporters would then feed into the criticism being lobbed by Cruz.