Republican strategists say Trump is raising the issue to new prominence now and will do so for the rest of the campaign to remind voters of the fundraising scandals that embroiled Bill Clinton’s White House in the late 1990s.

“It’s a visceral reminder of the Clinton scandals of the 90s that people vaguely remember. Remember George W. Bush ran in 1999 on a theme of restoring honor and dignity to the White House,” said Charlie Spies, a Republican lawyer and strategist. “I’m talking about the Chinese money scandals and the selling of the Lincoln Bedroom. That’s in the back of people’s minds, they don’t remember the specifics.”

Spies said the focus on the Clinton Foundation is designed to revive the general “ick factor” that “makes the ‘crooked Hillary’ insult by the Trump campaign resonate.”

Bill Clinton’s has conceded the problematic optics for his wife’s presidential campaign by informing employees and donors last week that the foundation would not accept donations from corporations or foreign sources if Hillary wins in November.

But non-partisan experts say the force of Trump’s attacks are blunted by his unwillingness to make public his returns as other nominees have done for decades.