President Trump arrives to speak to March for Life participants on Friday. A new Washington Post-ABC News poll shows that Trump’s approval rating has remained at a historically low level, compared with past presidents. (Jabin Botsford/The Washington Post)

Americans have reached a split-screen assessment of the state of the country at the end of President Trump’s first year in office, expressing the most positive views about the economy in nearly two decades while giving Trump historically low approval, according to a new Washington Post-ABC News survey.

This stark contrast between perceptions of the economy and assessments of the president continue a pattern that has existed since Trump was sworn in a year ago, that of a president whose personal actions and behavior have stirred controversy and created a political distraction in the face of steady growth, low unemployment and record gains in the stock market.

How voters weigh those two views will have a decided impact on the upcoming midterm elections. Democrats, who see an opportunity to take back control of the House and have a possible although uphill path to control of the Senate, will seek to make the November elections about Trump. Republicans hope perceptions of the economy will influence enough voters to hold down their expected losses enough to protect that House majority.

The new survey finds that 58 percent of all Americans give positive ratings to the state of the economy. That is the highest in a Post-ABC survey in 17 years and seven points higher than on the eve of Trump’s inauguration. At the same time, Trump’s approval rating has remained at a historically low level, compared with past presidents. Today, 36 percent approve of the job Trump is doing, while 58 percent disapprove, little changed over the past few months. Strong disapproval of the president, at 49 percent overall, remains twice as high as strong approval, which stands at 24 percent.

The public is evenly divided overall and deeply split along partisan lines on three major policy initiatives of the Trump presidency — the federal crackdown on undocumented immigrants, a reduction in federal regulations on businesses, and an effort to reduce the size of the federal workforce. More than 4 in 10 support those policies, and an almost-identical percentage oppose them. But the level of support is slightly higher than Trump’s approval rating, meaning that some Americans — particularly Democrats — who disapprove of the president support those policies.

On two of the biggest policy debates of the first year of Trump’s presidency — health care and taxes — the public comes down in opposition to the direction pursued by the administration and congressional Republicans. A majority (57 percent) say the continuation of the Affordable Care Act is a good thing, in essence an expression of relief that Republicans failed to repeal Obamacare as they had long promised to do.

Meanwhile, on the big tax bill passed by congressional Republicans and signed by Trump at the end of last year, 46 percent say it is bad for the country while 34 percent say it is good for the country. That is slightly better than when people were asked whether they supported or opposed the measure as it was being debated. Notably, 20 percent say they have no opinion or are ambivalent about the tax bill, which is likely to become a pivotal battleground for public opinion between the parties ahead of the November midterm elections.

The gap between the president’s low approval and the somewhat higher level of support for some of his policies reflects the disconnect between how people see the president and how they view some of his priorities. For example, 21 percent of Democrats who disapprove of the president say the crackdown on undocumented immigrants is a good thing for the country. The same percentage of disapproving Democrats say reducing federal regulations on business is good for the country.

For their part, Democrats are struggling to convey a message beyond being anti-Trump, with just over 3 in 10 saying they are presenting alternatives to Trump’s proposals. A 53 percent majority say the Democratic Party is mainly criticizing the president without offering alternatives.

As the president begins his second year in office, special counsel Robert S. Mueller III’s investigation into Russian interference in the 2016 campaign and possible cooperation, collusion or knowledge of what was taking place by associates of the Trump campaign continues. Trump has called the investigation a “witch hunt,” although it has produced two guilty pleas, including one from former national security adviser Michael Flynn, and charges against Paul Manafort, the president’s former campaign chairman, and an associate of Manafort’s.

Today, 50 percent of Americans approve of the way Mueller is proceeding compared with 31 percent who disapprove, with 19 percent expressing no opinion. In early November, 58 percent approved of Mueller’s handling, but in recent weeks, Republicans have targeted the investigation as biased. Among Republicans and GOP-leaning independents, approval of Mueller has dropped from 39 percent in November to 30 percent in the new poll.

Half of all Americans also say they believe Trump’s campaign colluded with the Russians, and an almost identical percentage say they believe the president tried to interfere with the investigation. Just over a quarter, 26 percent, say they believe there is solid evidence to buttress this latter assessment.

The impact of Trump’s leadership on the public is mixed to negative. Six in 10 Americans say he has accomplished little or nothing. That is better than the 65 percent who said this in November, before passage of the tax bill, but it is a worse rating than received by former presidents Barack Obama and Bill Clinton at a similar point in their first terms. A bare majority (53 percent) say Trump’s actions have made no difference to them and their families. The rest are roughly split about the effect of his presidency on them, with 26 percent saying his actions have hurt and 20 percent saying they’ve helped.

On the economy, Trump receives less credit for the gains seen over the past than does his predecessor, Obama. Fewer than 4 in 10, 38 percent, say the Trump administration deserves significant credit for the state of the economy while 50 percent say the Obama administration should get credit. Republicans and Democrats have sharply opposite views of where the credit should go. Among independents, one-third say Trump should get credit, compared with about half who give credit to Obama.

About 1 in 4 Americans rate the economy positively while disapproving of Trump’s job performance. Three-quarters of them are Democrats or Democratic-leaning independents, and most of the group says Obama deserves credit for the current state of the economy, not Trump. Even more important is the fact that almost all of them say Trump has acted in a way that is not presidential, one indicator of how his personal behavior has clouded his presidency.

The survey finds that Trump and the Republicans have so far failed to shift public opinion on key elements of their agenda. Republican leaders have said that the new tax law — the party’s biggest accomplishment to date — will provide lower taxes for most middle-class families. But at this point, 60 percent of Americans see the new measure overall as favoring the rich rather than the middle class or the poor.

Opposition to Trump’s proposal to build a wall on the U.S.-Mexico border to curtail illegal immigration remains strong, with 63 percent of Americans saying they are against it, including 52 percent who strongly oppose. But 71 percent of Republicans support the proposal, including 58 percent who support it strongly. The gulf between Republicans on one side and Democrats and independents on the other underscores why this part of border security has been a sticking point in budget negotiations between the two parties.

Congress has been at a stalemate over the future of the Obama-era policy that protected from deportation undocumented immigrants who were brought into the country as children. The issue has been a point of contention in recent days as Congress has struggled to reach a spending agreement. Trump rescinded the Obama program last fall and asked Congress to come up with a solution by March. So far that fix has eluded negotiators.

Public opinion is clear on this issue, with 87 percent of Americans saying they support a continuation of the protection for those undocumented young people who have completed high school or served in the military and who have no serious criminal record. On this, there is bipartisan agreement among overwhelming majorities of Democrats, Republicans and independents.

Trump’s behavior and fitness shape the other track of his presidency, to his detriment. Seven in 10 Americans say he has acted in a way that is not presidential, while a quarter say his behavior has been fitting and proper for the nation’s chief executive. About 2 in 3 say the president’s use of Twitter has hurt his presidency. A bare majority (52 percent) say he is biased against black people.

The president in a recent tweet, which came after a renewed round of questions about his stability in light of a new book that described him in unflattering terms, said he was both mentally stable and a “genius” for being able to win the White House in his first try for public office. On those two questions, Americans are almost split evenly about his mental stability but by better than 3 to 1 say he is not a genius.

 Trump recently underwent a physical examination that included a test aimed at detecting mild cognitive impairment. Ronny L. Jackson, the White House’s top physician, said the president had a perfect score on the test and dismissed questions about his mental competence.

The Post-ABC poll was conducted Jan. 15-18, 2018, among a random sample of 1,005 adults reached on cell and landline phones with a margin of sampling error of plus or minus 3.5 percentage points.

Emily Guskin contributed to this report.