A Michigan Senate debate turned ugly as Mike Rogers tried to tie his opponent Abdul El-Sayed to the Muslim Brotherhood and Hamas with no real evidence, while dodging questions on gun background checks.

• Rogers repeatedly implied El-Sayed, who is Muslim, has ties to extremist groups, but the claims rest on thin or made-up connections, including one about his mother.
• It turns out Rogers himself once said the U.S. should talk to "moderate" Muslim Brotherhood members and voted for aid to Egypt under its Muslim Brotherhood government, the opposite of what he accused his opponent of.
• On gun background checks, which poll with huge public support even among gun owners, Rogers refused to give a yes or no answer, saying it "depends."
• The race is seen as a test case: if El-Sayed loses, some Democratic insiders are expected to use it as proof that progressive candidates can't win, even though the party has been accused of giving him little support.

Outlook: Expect the attacks on El-Sayed's religion to continue as a campaign tactic, with national Democrats watching the race closely as a bellwether for progressive candidates.