India, Feb. 27 -- President Joe Biden's support for Israel's war against Hamas in Gaza will be put to a test on Tuesday in Michigan, home to a large Arab American constituency where Democratic voters have been urged to mark their primary ballots as "uncommitted."

Biden, a Democrat, and Republican former President Donald Trump will both want strong showings in their separate nominating contests. Michigan is a battleground state expected to play a decisive role in the head-to-head Nov. 5 election. Many in the large Arab American community are outraged, along with some progressive Democrats, over what they assert is Biden's unwavering support for Israel's Gaza offensive in which tens of thousands of Palestinians have been killed.

Late on M...