Ask AFL-CIO President Richard Trumka about the climate for unions on this Labor Day weekend, and he starts with something positive: a new Gallup poll showing public support for unions at its highest point since 2003.

"There's much more excitement about unions," Trumka says during an interview in his Washington, D.C., office just across Lafayette Square Park and with a view of the White House. He adds that, "over 61 percent of the people in the country support unions."

That number is significant, especially when you consider that just 8 years ago — in the wake of the deep financial crisis, automobile company bailouts and serious economic troubles that then-new President Obama was dealing with — that just 48 percent of Americans expressed a positive view of unions in a similar Gallup poll.

Trumka, the son of a mineworker and a former mineworker himself, says the improvement is because people recognize that unions are fighting for workers in an economy where most of the rules and levers of power are controlled by corporate interests.

The reality on a holiday celebrating the American worker is that labor unions face big challenges. Start with a tougher environment for organizing, the ongoing spread of so-called right-to-work laws that make it harder for unions to collect dues and grow membership by allowing workers to not join the union in workplaces that are represented by a union. On top of this, the Trump White House has been anything but labor friendly so far — despite promises to bring back manufacturing jobs that date back to the earliest days of Trump's campaign.

Last year's presidential election was a bad one for the labor movement.

Democratic nominee Hillary Clinton carried the votes of union households by 9 percentage points. But that's a big drop-off compared to the 18-percent margin among union voters for President Obama four years earlier. That shift most certainly had an impact in Midwestern battleground states.

Trump captured some of those voters by promising to revive American manufacturing, in part by cracking down on trade. He'd take on China and impose tariffs on steel, he pledged, and he'd renegotiate or tear up the North American Free Trade Agreement, NAFTA, which he said only encouraged U.S. companies to send work to Mexico at the expense of the jobs of American workers. That message resonated in union halls in the upper Midwest where job declines and factory closings have radically altered the economic landscape.

But the AFL-CIO's Trumka says, as appealing as that message may have been to many union members, Trump hasn't delivered as president: "His promises in the campaign haven't matched up with what he's done."

Instead, Trumka says, there's been an assault by the president and his administration on regulations that protect workers in so many ways. He begins listing them right off the top of his head: "Health and safety regulations that protect us from things like — protecting us from beryllium and silica... Overtime regulations that would have brought overtime to 4 or 5 million people. Consumer protection regulations. Regulations on Wall street. He's done away with a number of those things."

The challenge labor unions face now is getting their members who voted for Trump last year to see things the same way. The AFL-CIO president says the only way to do it is with the facts.

David Cohen, a political scientist at the University of Akron, had a close-up view of Trump's electoral success in the northeast corner of Ohio — where hulking, closed steel mills are a daily reminder of the decline in manufacturing jobs.

"A lot of these union people that went over to vote for Trump," Cohen says, "It's really unclear if these are loyal Trump voters or one-time Trump voters who decided to give somebody else a chance."

Many of those voters were simply unhappy with Democrat Hillary Clinton. But many decided to take a chance with Trump, or, as Trumka puts it, "a risk." Professor Cohen says Democrats need candidates who can win those voters back, at the presidential level, certainly, but also for congressional, state and local offices too.

Even so, he says there are obstacles the labor movement faces. There's the fact that a majority of states — 28 — now also have those right-to-work laws. According to Cohen, "That is a problem, because in order for unions to be strong across the country, or within the various states, they need numbers. They need as many members as possible."

With numbers come clout. And with clout comes candidates who embrace your agenda.

The AFL-CIO's Trumka acknowledges the challenge, and says it'll take smart, person-to-person contact — about what's at stake and what the facts are — with every union member. It's organizing and outreach, but at a level beyond what they've ever done before.

Copyright 2017 NPR. To see more, visit http://www.npr.org/.