In neighborhoods where yard signs often advertise high school sports teams, abortion-related messages are now emblazoned with dots on the front lawn. A cafe known for its chocolates and cheesecake has become a haven for abortion rights defenders and a source of outrage for opponents. Signs have been stolen, a Catholic church was vandalized earlier this month and the tension is palpable on the eve of the first major vote on the abortion issue since Roe v. Wade was overturned in June. “I’m really sad that this happened,” said Leslie Schmitz, 54, of Olathe, speaking of the abortion access landscape. “And crazy. Sad and mad.” There may be no greater motivator in modern American politics than anger. And for months, Republican voters angered by the Biden administration have been explosively energized for this year’s election. Democrats, meanwhile, have faced erosion with their base and significant challenges with independent voters. But interviews with more than 40 voters in populous Johnson County, Kan., this week show that after Roe’s downfall, Republicans no longer have a monopoly on outrage — especially in states where abortion rights are clearly on the ballot and especially in the Suburbs battlefield. “I feel very strongly about it,” said Chris Price, 46, a political independent who said he voted for Mitt Romney for president in 2012 before backing Democrats when Donald J. Trump was on the ballot. “Candidates who would support the ban on abortion, I would not support at all. Period.” Asked if threats to abortion rights had affected how motivated she felt to run in the midterm elections this fall, Natalie Roberts-Wilner, Democrat of Merriam, Kan., added: “Yes. Yes. Yes. For sure.” On Tuesday, Kansas will vote on a constitutional amendment that, if passed, could give the Republican-dominated legislature the ability to push for new restrictions on abortion or outlaw the procedure altogether. Neighboring states, including Missouri — which is separated from some rival Kansas suburbs by State Line Road, a thoroughfare dotted with abortion-related yard signs — have already enacted near-total bans. Voting is open to unaffiliated Kansans as well as partisans. And whatever the outcome, activists on both sides caution against drawing sweeping national conclusions from a question on the August ballot, given the complex crosscurrents.

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The amendment’s language itself has been criticized as confusing, and in an overwhelmingly Republican state, Democrats and unaffiliated voters are less likely to vote on Election Day. On the other hand, few voters said they would vote no on the amendment but might support Republicans in November — a sign that some who support abortion rights are still weighing on other political issues in the election. And nationally, a Washington Post-Schar School poll released Friday found that Republicans and abortion opponents were more likely to vote in November. But there’s no doubt that the abortion debate in the state’s most populous county — located in Kansas’ Third District, one of the nation’s most competitive congressional seats — offers the first major national test of how the issue resonates in the district of suburbs. Like other highly educated, moderate areas — from suburban Philadelphia to California’s Orange County — the Third District is home to a significant number of center-right voters who, like Mr. Price, felt comfortable with Mr. Romney in 2012. Democrats in the 2018 midterms, including Gov. Laura Kelly and Representative Charis Davids, and many have pushed back against Mr. Trump. Whether those voters will remain in the Democratic fold this year, with Mr. Trump out of office, has been an open question in American politics. Democrats are betting that anger over sweeping abortion restrictions will help the party hang on to at least some of these moderates, despite the extreme political opposition they face. Republicans insist that anger over inflation — and fear of a recession — will crowd out other concerns for a wide swath of voters. (In polls, far more Americans cite inflation or the economy as the biggest problem facing the country than abortion.) Tuesday’s vote will provide an early snapshot of attitudes and energy around abortion, if not a definitive prediction of how those voters will behave in the fall. “How much motivation is it really?” said Dan Sena, a Democratic strategist who led the 2018 House takeover, on abortion rights, adding that there have been signs of improvement for Democrats in some suburban districts recently. “How does it actually, when it stands on its own, move women, move portions of the electorate? And that will really give us insight and an opportunity to get an answer to that.” Limited public opinion polls have shown a fairly close if unpredictable race. “It looks like ‘Yes’ still has the lead, but it’s narrowed,” said Mike Kuckleman, the chairman of the Kansas Republican Party. Citing the Women’s Health Dobbs v. Jackson decision that handed control of abortion rights to the states, he continued, “A lot of that is because, I think, the Dobbs decision has spurred the pro-choice forces out.” The Kansas City Star reported Thursday that there has been an increase, so far, of about 246 percent in early in-person voting compared to the 2018 midterm primaries. Several polling places in both moderate and more conservative parts of Johnson County this week it was noisy all day, including in a storm and in the heat. And on Friday, Scott Schwab, the Republican secretary of state, predicted that about 36 percent of Kansas voters would participate in the 2022 primary, slightly higher than the 2020 primary. His office said the constitutional amendment “has increased voter interest in the election.” “I’ve talked to a lot of people who have said, ‘I haven’t participated before but I’m going to vote,’” Mr. Kuckelman said. Other Republicans said the abortion amendment and overturning Roe didn’t affect their commitment to vote in other races this year — which they’ve long had a strong turnout for. “There’s no more energy,” said John Morrill, 58, of Overland Park, who supports the amendment. “I was already very energized.” In the Olathe seat, which drew more conservative voters Thursday, Melissa Moore said she voted for the amendment because of her deep convictions that she opposes abortion. “I understand women who say, ‘I need to control my body,’ but once you have another body in there, that’s their body,” Ms Moore said. But when asked how the intense national focus on abortion has affected how she thinks about voting, she replied: “I tend to be always on.” Some others at the early voting site in Olathe said they were voting against the amendment and were leaning toward Democrats this fall. But they spoke in hushed tones and declined to give full names, citing concerns about professional backlash as an example of how dire the environment has become. Closer to the Missouri border, patrons at André’s, an upscale Swiss café, felt freer to openly voice their opposition to the amendment. The restaurant and store sparked controversy earlier this summer when employees wore “No” stickers or buttons and encouraged customers to vote, but several lunchtime diners made it clear they shared those views. “We just want to make sure people have rights to make choices,” said Silvana Botero, 45, who said she and a group of about 20 friends were all voting no and that she felt more enthusiastic about voting in November as well. In a nearby voting district, Shelly Schneider, a 66-year-old Republican, was more politically confrontational. Ms. Snyder opposed the amendment but planned to support some Republicans in November. But she was open to Mrs. Kelly, the Democratic governor, especially if the amendment passed. Passage of the amendment, he acknowledged, could pave the way for potentially far-reaching action by the Legislature. “I think Laura Kelly is kind of a hedge against anything that can come through,” he said. “It might provide some common sense there.” Mitch Smith contributed reporting.