Republicans and Democrats are delivering their closing arguments to midterm voters, aggressively stoking fears about the opposing party on health care and the rule of law with less than four weeks until the election.

Reeling from their failure to stop Justice Brett M. Kavanaugh’s confirmation to the Supreme Court, Democrats sought to regain their balance in the battle for the Senate on Wednesday by emphatically presenting themselves as guardians of the Affordable Care Act and its protection for Americans with preexisting medical conditions while casting Republicans as threats to that basic principle.

President Trump, in an op-ed riddled with falsehoods or misleading statements, painted a dire portrait of what would happen under a “Medicare-for-all” plan favored by many Democrats, and he portrayed the party’s efforts as part of a wider “radical” push toward socialism.

The strategies are part of a broader trend that has emerged in campaigns across the country, with control of Congress at stake on Nov. 6. Republicans are determined to brand Democrats as extremists who they argue should alarm most voters. Democrats are characterizing Republicans as destructive crusaders against landmark laws protecting everyday people.

“When you see an angry mob beating on the doors of the Supreme Court, scratching at the doors, when you see Democrats like Hillary Clinton saying you cannot be civil to someone who disagrees with you and promising civility will return once the Democrats take over Congress, that’s just radical, that’s extreme,” said Sen. Ted Cruz (R-Tex.), who is in a competitive race that could decide control of the Senate.

The raw emotion on both sides of the Kavanaugh fight was still palpable Wednesday. Sensing little to be gained by re-litigating it, Democrats resolved to turn the page to a subject they have made a cornerstone of their campaign to retake Congress: health care.

Led by Sen. Tammy Baldwin (D-Wis.), who faces reelection in a state that Trump won in 2016, Senate Democrats fell one vote short in a bid to overturn the administration’s expansion of short-term health insurance plans that do not have to cover people with preexisting medical conditions or provide the kind of care that the ACA requires, such as coverage for births and substance abuse.

But by forcing a roll call on what they term “junk” plans, Democrats managed to put a spotlight on a key issue they argue will cut their way in the election by appealing to voters in both parties. Only one Republican, Susan Collins of Maine, voted with them.

In a speech on the Senate floor, Baldwin pointed to a plan sold in her state that she said does not cover hospital care on a Friday or Saturday. “So, it will just be your bad luck if you happen to get sick and need health care on the weekend,” she said.

Trump, in an op-ed published by USA Today, sought to cast himself as the protector of the government-run Medicare program that benefits seniors and claimed that by trying to expand it, Democrats are seeking to “eviscerate” it. He also accused Democrats of being “radical socialists who want to model America’s economy after Venezuela.”

The op-ed contained several misrepresentations of Democratic positions, including stating that a “Medicare-for-all” plan means “that after a life of hard work and sacrifice, seniors would no longer be able to depend on the benefits they were promised.” But the plan, at least in theory, seeks to expand benefits rather than curb them. “Bottom line, he’s trying to frighten seniors,” said Sen. Bernie Sanders (I-Vt.).

Trump also writes that Democrats “will seek to slash budgets for seniors’ Medicare, Social Security and defense.” While some Democrats have pushed for cuts in defense spending, they generally have pushed to expand Social Security benefits, not cut them.

The claims made in the op-ed were a central point of the messaging efforts by the White House. Senate Republicans, meanwhile, attacked Baldwin for trying to reduce consumer choice and argued for pursuing new ways to cover people with preexisting conditions outside the ACA, which is also known as Obamacare.

The GOP onslaught did not stop with health care. National Republican Senatorial Committee Chairman Cory Gardner (Colo.) angrily decried threats of violence against Republicans in reaction to Kavanaugh. “My wife received a text message of a graphic beheading,” he said. Senate Majority Leader Mitch McConnell (R-Ky.) placed all the blame on Democrats for raising tensions.

“We know who the culprits are,” McConnell said after protests during the Kavanaugh confirmation, when demonstrators challenged lawmakers in the hallways of the Capitol.

Republicans are defending a 51-49 majority in the Senate. They say Kavanaugh’s confirmation has ignited a wave of energy among conservative voters in the 10 states Democrats are defending where Trump won.

Republicans concluded long ago that divisive cultural and political fights would help them in those states. So they have stoked battles over immigration, the courts and now, the angry Democratic reception to Kavanaugh, using words and imagery meant to evoke horror.

Democrats have tried to focus on what they call “kitchen table” issues in those states, issues like health care and taxes that they say appeal to voters across the political spectrum. A Wesleyan Media Project study of ads in federal races during September showed 1 in 2 pro-Democratic spots mentioned health care.

Many of their commercials have been designed to promote an emotional response. Rep. Jacky Rosen, the Democratic nominee for Senate in Nevada, released an ad this week calling her opponent, Republican Sen. Dean Heller, “Senator Spineless,” for his refusal to stand up to his party’s effort to repeal and replace the ACA last year.

Senate Minority Leader Charles E. Schumer (D-N.Y.) singled out a Republican lawsuit against the ACA that two GOP state attorneys general running for Senate signed: Josh Hawley of Missouri and Patrick Morrisey of West Virginia. Both are in races that are key to determining whether the Republicans will keep their majority.

“Come Nov. 6, the difference between the parties on health care will be crystal clear,” Schumer told reporters Wednesday.

The suit argues that the law is not constitutional, and the Trump administration opted not to defend the law, giving Democrats an opening to amplify their attacks and prompting Republicans to scramble to explain it.

“I’m sure the judge will decide it, and I’m sure that won’t be the end of it,” said Sen. John Cornyn (R-Tex.), McConnell’s top deputy. “This is not really a near-term issue.”

In the battle for the House, the divisive atmosphere has been less helpful to Republicans, given the high number of swing, suburban seats up for grabs, where moderates appear to be turning away from the president and his party. One influential Republican, speaking on the condition of anonymity to be candid, predicted that the party wouldn’t be able to hold its House majority if it had “super glue” on its hands.

House Minority Leader Nancy Pelosi (D-Calif.), seeking to reclaim the speaker’s gavel next year, highlighted on Wednesday Trump’s failures to fulfill promises — issuing a report showing rising health insurance premiums and prescription drug prices, stagnant wages and uneven benefits from last year’s GOP tax bill.

House Democratic money remains firmly behind health-care messaging. On Wednesday, the largest Democratic super PAC focused on House races debuted ads targeting Rep. Steve Knight ­(R-Calif.) for his support of the tax bill, which included a provision undoing a pillar of the ACA — the requirement that Americans have insurance or pay a penalty.

The ads feature activist Ady Barkan, who has the degenerative disease ALS and has been a fixture of Capitol Hill protests against Republican policies. “Steve Knight betrayed my family and yours,” he says in the ad. “On Nov. 6, let’s send him home.”

At a signing ceremony for a bipartisan bill to help Americans find out whether they can save money on prescriptions by paying cash rather than using insurance, Trump said, “In less than two years, we have taken unprecedented action to make health care more affordable and to give patients more choice and more control.”

Democrats on the ballot across the country took a very different view. “There’s almost not a week that goes by that Republicans don’t make it clear that their number one priority in Congress is to try to weaken protections for people with preexisting conditions,” said Sen. Chris Murphy ­(D-Conn.), who is running for reelection.

Erica Werner, Mike DeBonis and Felicia Sonmez contributed to this report.