Bitter infighting among President Trump’s top health officials — as well as his own shifting demands on signature policies — have undermined key planks of the president’s health-care agenda as he girds for a tough reelection campaign, according to current and former administration officials.

Though polls show the issue is critically important to voters, Trump has failed to deliver on his most important health-care promises. His plan to dramatically lower the prices consumers pay for prescription drugs has been stalled by internal disputes, as well as by technical and regulatory issues, said six people with knowledge of the process. And an administration plan to replace the Affordable Care Act has not materialized even as the administration seeks to strike down the law in federal court.

In recent days, the conflicts between Health and Human Services Secretary Alex Azar and Centers for Medicare and Medicaid Services Administrator Seema Verma have spilled into view with damaging leaks about Verma’s use of contractors to boost her profile at a cost of nearly $3 million to taxpayers and an attempt to recoup $47,000 from the government for jewelry and clothing stolen on a work trip, first reported by Politico. She, in turn, assigned top staffers to probe the leaks and concluded they came from the HHS general counsel’s office. A person close to Azar denied he had anything to do with the leaks.

Acting White House chief of staff Mick Mulvaney met with the pair Wednesday afternoon in the latest bid to end the conflict, although Trump and Vice President Pence have made past attempts to do so, to no avail. While Verma had enjoyed high standing with the White House for her public attacks on Democratic health-care proposals and championing of work requirements in Medicaid, her reputation has been damaged by reports about her questionable use of taxpayer money, according to two senior officials.

Aides said the meeting was a last-ditch effort to keep them both in the administration and persuade them to work together.

While conflicts within agencies and the White House are not unusual, officials said the tension among various players has grown untenable in recent months.

“This isn’t a band of brothers. It’s each man on his own. It’s a group of mercenaries,” a senior administration official said, noting that senior officials pursue differing and even conflicting policies.

The White House played down the conflict. “There’s no daylight between the White House and HHS as we work to implement the President’s policies and improve the American healthcare system for everyone,” White House spokesman Judd Deere said in a statement.

This account of the administration’s efforts on health policy is based on interviews with more than a dozen current and former senior administration officials, as well as lobbyists and outside advisers, most of whom spoke on the condition of anonymity to candidly describe sensitive discussions and conflicts.

A turning point in Azar and Verma’s relationship came earlier this year when Verma and White House Domestic Policy Council Director Joe Grogan argued to Trump that the nearly $200 billion price tag on Azar’s signature drug rebate proposal, which had called for ending drugmakers’ rebates to insurance middlemen, was exorbitant and would raise Medicare premiums just before the election. Trump subsequently killed the proposal. Verma and Azar’s relationship deteriorated after the meeting, people close to them said.

The two drug pricing proposals Trump has championed — allowing the importation of certain cheaper drugs from Canada and basing the price of some Medicare drugs on the lower prices paid by several other countries — are both stalled by internal disputes, as well as technical and regulatory issues, said six people with knowledge of the process.

Meanwhile, Verma and her team spent six months working on an ACA replacement plan that she presented to Trump in the Oval Office. Azar opposed the plan because it contained subsidies, and there was widespread disagreement on it within the White House, a White House official said.

Verma and her backers believe she has become the victim of a “smear campaign” involving “strategic leaks coming from inside HHS,” said one person familiar with the perspective of her agency. Grogan and some other administration officials have complained bitterly about HHS management, while Verma told White House officials and the HHS general counsel’s office that some women in the department have faced a difficult work environment, officials said.

But those conflicts are not the only factor complicating Trump’s efforts to craft a coherent health-care message.

Senior advisers have also found it challenging to navigate the president’s moods, interests and mercurial personality, which has led aides to pursue plans that were ultimately scrapped, at times for political reasons. That was evident when Trump announced in September that the administration would ban all flavored ­e-cigarettes, only to back down last month after campaign advisers said it could lead to job losses and hurt his reelection prospects.

While nearly everyone interviewed for this article acknowledged the administration has not met its biggest health-care promises, they hailed other measures as achievements.

They said they have widened access to inexpensive insurance that does not meet the health-care law’s standard and pointed to Congress’s passage last year of a broad bipartisan bill to address the opioid epidemic that Trump signed into law. They also touted a recent rule to increase price transparency by hospitals and health insurers, slated to go into effect in January 2021; an initiative to improve kidney care and organ transplantation; changes to Medicare that resulted in premiums dropping more than 20 percent in Medicare Advantage; an initiative to end the HIV epidemic by 2030; and a rule that allows employers to pay for their employees’ health insurance by subsidizing the price of Obamacare individual market coverage that goes into effect in January.

“It’s hard to change things administratively and we were able to accomplish a great deal, I think, as well as lay out a vision of where the Republican Party should be on health care,” said Brian Blase, former special assistant to the president for health-care policy.

The president’s defenders and some administration officials say the president has changed the conversation around drug pricing by forcing Republicans to talk about an issue they traditionally ceded to Democrats, and by pressuring pharmaceutical companies to lower some prices, if only temporarily, after shaming some of them by name on Twitter. Retail drug prices fell by 1 percent in 2018, a government report showed, but voters have yet to see significant changes in what they pay at the pharmacy.

That changed conversation has yet to find its way into drug pricing legislation supported by Republican leadership, however. A bipartisan drug pricing measure that would cap seniors’ out-of-pocket costs in Medicare, which was negotiated by Senate Finance Committee Chairman Charles E. Grassley (R-Iowa) and ranking Democrat Ron Wyden (Ore.), looks increasingly unlikely, even though it is backed by the White House.

Senate Majority Leader Mitch McConnell (R-Ky.) has indicated he will not bring a measure to the floor that doesn’t have the backing of his caucus, a White House official said. But the official added that Trump has not yet pushed the bill with McConnell directly.

“If Trump wanted to act on health care, he needs to use the bully pulpit,” said James Wallner, a former Republican Senate aide. “He has allies in the Senate, but the question is why aren’t they advocating for him?”

Caitlin Oakley, a spokeswoman for Azar, said the secretary has talked with numerous lawmakers trying to rally support for legislation to lower health-care prices — “a testament to this is the multiple drug pricing bills being considered on the Hill,” she said.

Also stalled amid fierce lobbying by doctors and insurers are congressional efforts to address surprise medical billing, which are backed by the White House as well.

Meanwhile, several of the administration’s health regulations have been blocked or held up by federal courts, including a mandate that drug companies put the list prices of their medicines in television ads and several states’ efforts to implement work requirements in Medicaid, one of Verma’s major initiatives.

Officials’ last hope for action before the election rests with the proposal to allow states to import drugs from Canada and another to base the price of some drugs in Medicare on the lower prices paid by other countries.

Trump is especially eager to get out the importation proposal so some voters have access to cheaper drugs from Canada before the election, according to two officials. But the effort has been mired in conflicts between the Food and Drug Administration and the HHS secretary’s office.

Officials at the FDA, which is responsible for drug safety, balked at the White House request for a rule that would allow broad importation. They contend that under existing law, few, if any, drugs are eligible for importation because they must meet strict safety standards and qualify under specific conditions, including not violating existing U.S. patents.

Trump “doesn’t want to hear anymore that it’s never going to work,” a senior White House official said. “He wants to be disruptive.”

The secretary’s office is now working to recast the rule to meet the White House’s demands. Azar is “challenging the FDA to think about importation in new ways for the first time,” a senior administration official said.

Officials said the rule could be ready early next year, though they remain uncertain.

Health officials had also drafted a rule creating an international pricing index for some Medicare drugs administered in hospitals or doctors’ offices. Under the initial proposal, the United States would pay no more than 120 percent of the average price paid by several other countries. Over the summer, however, Trump demanded it be rewritten because he did not want the United States paying more than other countries. As officials have worked to satisfy Trump’s demands, they said they have encountered technical and legal issues.

“I have to be very honest with myself and say that we may have more people talking about patient affordability, more people talking about benefit design and rebates, but we didn’t do anything,” another former senior administration official said. “There’s nothing there that makes particularly makes me feel like, ‘Hell yeah, we did this.’ ”