Messianic Jews follow Jewish tradition and custom, but believe the Messiah (Moshiach) has already come -- in the person of Jesus. Basically, they're fundies who happen to worship Friday night instead of Sunday morning. The best-known example is Jews for Jesus.
The Messianic Jewish Alliance of America paid Santorum $6,000 to speak at its 2010 annual conference, according to a filing released Wednesday showing a total of nearly $95,000 in speaking fees that Santorum previously failed to disclose.
The alliance supports Messianic Judaism, which embraces Jewish heritage and customs but holds the fundamental Christian belief that Jesus is the son of God. Its beliefs are similar to those of the group Jews for Jesus, which has drawn particular ire from Jewish leaders for its proselytizing efforts.
But Joel Chernoff, CEO of the Messianic Jewish Alliance, said “Israel could not have a better friend than” Santorum, an observant Catholic whose speech to the group dealt with the threat of Islamic extremism. Chernoff said he personally supports Santorum, “and I think most Messianic Jews would probably say that,” though he conceded Santorum’s passing affiliation with his group “could be a factor” with traditional Jewish voters.
Some Jewish leaders have denounced Messianic Judaism as “religious fraud” intended to convert Jews to Christianity.
Aside: My own encounter with a Messianic Jew came when he was the board chair of my former agency, who was trying to run the place. I figured the one day I wouldn't have to worry about running into him was Yom Kippur. And I was wrong.