Another Tuesday, another critical day for the 2012 Republican presidential contenders.
This time the locations are Michigan, where most polls close at 8 p.m. ET, and Arizona, where voting ends at 9 p.m. ET. The story political junkies are watching closest: Will former Massachusetts Gov. Mitt Romney, a Michigan native, hold off a strong challenge there from former Pennsylvania Sen. Rick Santorum?
Also on the ballots, of course: former House Speaker Newt Gingrich and Rep. Ron Paul, R-Texas.
Once again, we're helping out the Elections Desk by live blogging. Starting around 7 p.m. ET, you should be able to see our latest updates right on the NPR.org homefront. Join us if you'd like to follow along.
Also, many NPR stations will be broadcasting live coverage starting at 9 p.m. ET — and that programming will also be webcast on NPR.org.