Rep. Justin Amash headed home for his primary today against a well-funded challenger with one last controversial vote.

The Michigan Republican joined just seven other House colleagues (four Democrats and three other GOPers) on Friday to vote against sending $225 million in aid to Israel for its Iron Dome missile defense system.

It’s the rare vote that is unpopular with both Democrats and Republicans, especially given the current conflict between Israel and Hamas in the Gaza strip, and it was the House’s last vote before the start of the five-week August recess.

Amash explained the vote in a statement:

"I support Iron Dome (see We're supposed to offset all new spending with cuts elsewhere. Congress did so with the border bill (which is for our own country), but not with the additional Iron Dome funding. Our debt is approaching $18 trillion. Even our own defense spending is offset, so this was a clear violation of our rules."

Others disagree. Hal Ostrow, a politically active attorney from Amash’s district who backs his primary challenger, said the vote may be a problem for the congressman’s evangelical constituents.

“He’s consistently been among the most anti-Israel members of Congress, so the vote is disappointing but not surprising,” he said.

Amash is sometimes seen as retired-Rep. Ron Paul’s congressional heir, famous for voting against bills with broad bipartisan support and explaining all his votes on his Facebook page.

His primary opponent, Grand Rapids businessman Brian Ellis, has looked to make hay from Amash’s many controversial, libertarian-leaning votes; his campaign site has a page called "Amash Bizarre Votes," and his campaign has regularly sent out emails highlighting these votes (29 "Amash Bizarre Vote" emails, by one count).

Ellis wasn't shy about criticizing this vote.

"I strongly support the Iron Dome that protects our ally Israel from terrorist missiles,” Ellis said in a statement. “Unlike Justin Amash, who was the only Michigan Member of Congress to vote against the Iron Dome Missile defense system, I would have stood with our ally Israel and voted yes."

Despite Amash’s unorthodox voting record, Ellis’ attacks show little sign of impacting the primary’s outcome. Many Michigan Republicans predict that Amash will win today, and probably by a lot.