I have written this new piece for Slate. It begins:

Set aside, for a moment, the Supreme Court’s decision Monday upholding Indiana’s voter-identification law. It’s another little-noticed election law in the state that could come into play during next week’s Clinton-Obama contest for the Democratic presidential nomination. Republicans and independents can vote in Indiana’s Democratic primary. But this quirky state law gives voters the right to challenge other voters at the polls for not being sufficiently loyal to the political party in whose primary they are voting.”

For the election geeks out there (hi Doug!), the relevant code sections are the following two:

IC 3-10-1-6
Eligible voters
Sec. 6. A voter may vote at a primary election:
(1) if the voter, at the last general election, voted for a majority of the regular nominees of the political party holding the primary election; or
(2) if the voter did not vote at the last general election, but intends to vote at the next general election for a majority of the regular nominees of the political party holding the primary election;
as long as the voter was registered as a voter at the last general election or has registered since then.
and
IC 3-10-1-9
Challenging voter
Sec. 9. A voter in a precinct may challenge a voter or person who offers to vote at a primary election. The challenged person may not vote unless the challenged person:
(1) is registered;
(2) makes:
(A) an oral or a written affirmation under IC 3-10-12; or
(B) an affidavit:
(i) that the challenged person is a voter of the precinct; or
(ii) required under IC 3-10-11 if the voter declares that the voter is entitled to vote under IC 3-10-11; and
(3) either:
(A) at the last general election voted for a majority of the regular nominees of the political party for whose candidates the challenged person proposes to vote in the primary election and intends to vote for the regular nominees of the political party at the next general election; or
(B) if the challenged person did not vote at the last general election, intends to vote at the next general election for a majority of the regular nominees of the political party holding the primary election.

As I note in the Slate piece, “Given the way it’s constructed, prosecuting someone under this law looks quite difficult–unless someone is dumb enough to blog about lying on an affidavit, how would prosecutors prove how the voter voted last time or that he lacks the intention to vote for a majority of Democrats at the next general election? And there are questions about the constitutionality of this provision.” On the constitutional question, at least for voters who voted in the last election, is this not a two year disaffiliation provision, like that struck down by the Supreme Court in Kusper v. Pontikes. I’d certainly advise the Indiana legislature to change this law before the next election, or else face a lawsuit seeking to strike it down.
In any case, we’ll see if challengers materialize at the polls on Tuesday. Thanks so much to a reader for initially bringing the odd Indiana code provisions to my attention.