Republicans are poised to unleash a barrage of negative advertising ahead of the midterm elections, betting that scorched-earth campaigning can overcome a challenging political environment. President Trump's disapproval rating has hit its highest level of his second term, and Democrats are gaining ground on the economy while showing greater voter motivation across the country.

The party's main political committees and allied groups have built a staggering financial advantage of roughly $600 million over Democratic counterparts. Republican pollster Patrick Ruffini expects "tens of millions of dollars spent on the personal negatives of some of these candidates," particularly in key Senate races in Maine and potentially Michigan. Just 23 percent of Americans approve of Trump's handling of the cost of living, according to a new AP-NORC poll.

Negative campaigning has a long history in American politics and can be effective, though it risks being wildly misleading. Republicans are hoping to turn the elections into choices between individual candidates rather than a referendum on Trump. "Gravity comes for everyone at a certain point," said Tim Persico, a former executive director of the Democratic House campaign arm. The party faces the dual challenge of persuading swing voters while motivating a demotivated base.