First, the three Messianic Jews that I can think of off the top of my head--well, four; maybe five: Kathie Lee Gifford nee Epstein, Josh Groban, Lenny Kravitz, and Jada Pinkett Smith (Sefardit Yehudit, and not Messianic if she is into Scientology)--oh, and Julie Margolies (actually, Julianna Margulies--wrong spelling, right name. And whether she's related to the Margiewiczes-Morgiewiczes, I do not know. [Update: Actually, her mother is Messianic Jewish. This doesn't mean that Julianna Margulies isn't, though; although she did marry her husband in a Non-Messianic Jewish ceremony.]).
Meanwhile, is Michelle Obama a Kohenet or at least of Kohen descent?
"Mrs. Obama’s paternal great-grandmother was Rosella Cohen of Georgetown, S.C., and her origins remain something of a mystery. We can’t say with certitude who Rosella’s parents were, but some historical documents suggest that they were Caeser and Tira Cohen, who were born into slavery in Georgetown. The surname Cohen suggests a possible link to the white Cohen family, a very prominent Jewish family in Georgetown in the early 1800s. Moises Cohen, who emigrated from London to South Carolina around 1750, was the first chief rabbi of Charleston’s Congregation of Beth Elohim, the birthplace of Reform Judaism in the United States. His two sons, Abraham and Solomon, moved to Georgetown and became deeply involved in its civic and political life. Abraham, who fought in the Revolutionary War and served as the town’s postmaster, met with George Washington when the American president visited Georgetown in 1791. Solomon was a director of the Bank of the State of South Carolina and his son, Solomon Jr., was elected to the South Carolina State Senate in 1831. Several Cohens were also slave owners. Most of the Cohens eventually left Georgetown for Charleston, but before they did, it is possible that a member of this prominent Jewish family owned Caeser or his parents."
Assuming that Caesar Cohen was a "mamzer", Michelle Obama would be a 1/16th Jewish and Koheni. With Tira Cohen (as far as I know), there's no evidence that she was born of a Jew, let alone a Kohen. So, Michelle Obama would be a (follow me here) paternal-paternal(?)-maternal Kohenet (or if you'd like to go down the line, maternal-paternal(?)-paternal Kohenet).
Meanwhile, is Michelle Obama a Kohenet or at least of Kohen descent?
"Mrs. Obama’s paternal great-grandmother was Rosella Cohen of Georgetown, S.C., and her origins remain something of a mystery. We can’t say with certitude who Rosella’s parents were, but some historical documents suggest that they were Caeser and Tira Cohen, who were born into slavery in Georgetown. The surname Cohen suggests a possible link to the white Cohen family, a very prominent Jewish family in Georgetown in the early 1800s. Moises Cohen, who emigrated from London to South Carolina around 1750, was the first chief rabbi of Charleston’s Congregation of Beth Elohim, the birthplace of Reform Judaism in the United States. His two sons, Abraham and Solomon, moved to Georgetown and became deeply involved in its civic and political life. Abraham, who fought in the Revolutionary War and served as the town’s postmaster, met with George Washington when the American president visited Georgetown in 1791. Solomon was a director of the Bank of the State of South Carolina and his son, Solomon Jr., was elected to the South Carolina State Senate in 1831. Several Cohens were also slave owners. Most of the Cohens eventually left Georgetown for Charleston, but before they did, it is possible that a member of this prominent Jewish family owned Caeser or his parents."
Assuming that Caesar Cohen was a "mamzer", Michelle Obama would be a 1/16th Jewish and Koheni. With Tira Cohen (as far as I know), there's no evidence that she was born of a Jew, let alone a Kohen. So, Michelle Obama would be a (follow me here) paternal-paternal(?)-maternal Kohenet (or if you'd like to go down the line, maternal-paternal(?)-paternal Kohenet).