A woman dressed as a suffragette casts her ballot for the midterm elections at the Polk County Election Office on October 8, 2018 in Des Moines, Iowa.Today was the first day of early voting in the state.

Republicans and Democrats will spend the final month of the midterm election campaign in an unprecedented test of the potency of gender politics.

With the gender gap already a chasm during Donald Trump's presidency, the fight over Brett Kavanaugh's Supreme Court confirmation closed with dueling displays of male and female rage. Deepening familiar party divisions, an outsized number of battleground House and Senate races on Nov. 6 match Democratic women candidates against Republican men.

Republicans hope those male candidates, the symbolic representatives of traditional gender roles, benefit from a backlash against allegations about Kavanaugh and Trump-stoked fears about the vulnerability of other men to similar attacks. With polls generally on their side, Democrats hope women candidates have added drawing power with unhappy voters seeking change.

Female office-seekers "should be able to benefit from it," said Ruth Mandel of the Center for American Women and Politics at Rutgers University. "This is a moment when different faces, different voices are a high priority."

At the same time, the decisive vote to confirm Kavanaugh blurs that formulation. Cast by a Republican woman, Sen. Susan Collins of Maine, it reinforced the idea that party label matters more than gender in how politicians behave.

That has been the lesson of recent years as growing numbers of women have entered politics. Gender stereotypes among voters, which once ascribed strength to male candidates and empathy to female ones, have almost entirely yielded to the tribal magnetism of partisanship.

Yet Trump has sent fresh electricity into the politics of gender since he defeated Hillary Clinton for the presidency two years ago. The share of women who call themselves Republicans has fallen, while the share who call themselves Democrats has risen.

Anti-Trump sentiment has been particularly pronounced among college-educated white women. That once Republican-leaning constituency now favors Democrats for Congress by 53 percent to 31 percent, according to the most recent NBC News/Wall Street Journal poll.