Republicans and Democrats don’t agree on much, but most agree on this: The federal government isn’t working the way it should. Instead of fixing problems and boosting the economy, recent presidents have seemed to lurch from crisis to crisis — from Iraq and Hurricane Katrina under George W. Bush to Islamic State and the Obamacare rollout under Barack Obama.

The problem is real, and it’s getting worse. One recent study found that “government breakdowns” have occurred twice as often under Presidents Bush and Obama as during the decades before.

That’s driven public trust in government to historic lows. Last year, the Pew Research Center found that only 19 percent of Americans trust the federal government to do the right thing most of the time.

Partisans will tell you the reason is simple: People in the other party have messed things up. Republicans say big government doesn’t work (even though it once did — better, at least, than it’s working now). Democrats say that’s because Republicans won’t let the government work.

In a smart, concise book, “Why Presidents Fail and How They Can Succeed Again,” Elaine C. Kamarck, who worked on federal government reform in the Bill Clinton administration, argues persuasively that Bush and Obama failed to grasp the importance of managing the federal bureaucracy. As a result, she writes, they brought spectacular failures upon themselves.

“In modern America, the government the president leads is an afterthought — until it takes down his presidency,” she writes.

“Voters are angry at politicians, and that’s understandable,” Kamarck told me this week. “They’re angry because they want a president and Congress that can get things done, and that’s not happening. Some think it’s because the politicians are corrupt. But I’m sorry; George W. Bush’s problems didn’t come from corruption, and neither did Obama’s. And a lot of voters have decided that they don’t want politicians any more — that we ought to get nonpoliticians to do the job. But … our real problem is that we’ve had a series of presidents who were so inexperienced in governance that they neglected a big part of their job, and that led to dramatic failures.”

The neglected part of the president’s job, she argues, is old-fashioned management: negotiating with Congress, implementing programs carefully and keeping an eye on the vast federal bureaucracy to stop crises before they happen.

Over the past few decades, she notes, the government has become more complex, but the budgets for managing its bureaucracies (like the Center for Medicare and Medicaid Services, which bungled the Obamacare rollout) have gotten smaller.

Presidents and their aides have assumed that good politics and persuasive rhetoric could cover up flaws in performance. They were wrong.

The task for voters and journalists in the rest of the campaign is to press the candidates to explain how they plan to accomplish what they’ve promised.

“George W. Bush got some very big things wrong in spite of having a brilliant political strategy,” she writes. “And Barack Obama seems to be the epitome of someone who is a brilliant campaigner with a lackluster ability at governing.”

Kamarck is a Democrat, but she’s tough on Obama. On Obamacare, she writes, “An inspirational and intellectual president failed the most basic test of leadership: creating reality from rhetoric.”

What’s the lesson for voters facing this year’s choice between Donald Trump and Hillary Clinton?

“Easy question,” Kamarck said. (She’s still a Democrat, after all.)

“Clinton talks about the importance of governing and having a Congress that can get things done. She has lots of plans, lots and lots of plans. That at least means she has a grasp of the problems. He has no plans at all.”

But what about Trump’s claim that as a purportedly successful businessman, he can force the federal government to shape up fast?

It doesn’t work that way, Kamarck warns.

“The government is different from the private sector in fundamental ways,” she notes. The president administers programs, but Congress acts like a disorderly and willful board of directors — a problem Trump has never dealt with in his privately held companies, according to Kamarck. “In most of the federal government, you can’t just walk in and say, ‘You’re fired.’”

In the long run, Kamarck says, the next president needs to focus on basic management precepts: Pay more attention to implementation. Do performance audits on the bureaucracy. Set up an “early warning” system so you aren’t blindsided by breakdowns.

Meanwhile, the task for voters and journalists in the rest of the campaign is to press the candidates to explain how they plan to accomplish what they’ve promised.

“This is the time to ask: OK, how are you going to do it? They both agree that the most important priority is creating jobs. OK, who has the better plan?”

We already know what the candidates want to do; we know their goals and policies are starkly different. What we don’t know, in much detail, is how they would actually govern if elected, especially in the case of Trump.

So let’s stick to a simple question: How are you going to get it done?

Doyle McManus is a columnist for the Los Angeles Times. Readers may email him at doyle.mcmanus@latimes.com.