ALBANY, N.Y. — It must have seemed like such a fine idea.

On Friday, Gov. Andrew M. Cuomo was standing alongside his mother, Matilda, and Hillary Clinton celebrating the “grand opening” of the eastbound span of a gleaming bridge bearing his father’s name. Emotional words were spoken; selfies were taken.

But that span never opened as planned on Saturday as engineers cited a “potentially dangerous situation” involving the old and adjacent Tappan Zee Bridge, which is being taken apart. What had seemed a perfectly orchestrated ribbon-cutting, just days before Thursday’s primary, quickly morphed into a cudgel for the governor’s opponents, who accused him of putting politics above public safety and called for a federal investigation.

Then, a second problem erupted for Mr. Cuomo on Saturday, when a flier landed in mailboxes of Jewish New Yorkers: a political mailer, paid for by the State Democratic Party that Mr. Cuomo funds, tying together a photograph of his opponent, Cynthia Nixon, and the loaded words “anti-Semitism.” The flier drew swift rebukes from fellow Democrats as Mr. Cuomo distanced himself from its content.

“I am the mother of Jewish children,” Ms. Nixon said on Sunday, demanding a full account of how the piece she said was a “smear campaign” was approved, and for Mr. Cuomo to record a robocall for voters apologizing for “calling me an anti-Semite.”