Hillary Rodham Clinton had planned to spend the last two weeks of August on vacation, unwinding and fund-raising on the exclusive shores of Long Island. But, as it turns out, this is no time for a vacation.

Amid concerns about Mrs. Clinton’s softening poll numbers and her exclusive use of a personal email server as secretary of state, she will interrupt her Hamptons stay next week to travel to the Midwest and try to shift attention back to her campaign message by unveiling new policy positions.

She will then return to the Hamptons, where she and former President Bill Clinton are renting a beachside estate in Amagansett that costs $100,000 for a two-week stay, and will attend several $2,700-per-person fund-raisers hosted there by her wealthy friends.

With questions about Mrs. Clinton’s use of private email persisting — a federal judge said Thursday that the practice did not comply with government policies — and Vice President Joseph R. Biden Jr. considering seeking the Democratic nomination, the late-August doldrums have proven anything but.