Republican Senator Chuck Grassley held his composure as the agitated chatter reached a low boil at the Floyd County Court House in Iowa.

The seven-term senator, pacing with his hands often at his hips, endured a stinging cross-examination from members of the public at the overflowing town hall Thursday in Charles City, about two hours north of Cedar Rapids.

"I voted for you many years ago — when I thought you were moderate," one woman told Grassley, who since 1981 has been serving the swing state that voted Republican in the 2016 presidential election after two terms backing the Democrats.

"You've changed," the woman added.

Grassley speaks with a protester at the packed town hall. Angry constituents expressed displeasure with the Trump administration's policies. (Matt Kwong/CBC)

There were jeers and murmurs of agreement.

"Where's the moderate?" another woman sitting in a jury box complained.

Grassley's constituents had a thing or two, sometimes three, sometimes more, to say to him. If there were a common thread, it was that many remarks were meant for him to pass to President Donald Trump in Washington.

Their grievances included the president's alleged ties to Russia and the Kremlin's meddling in the election, his refusal to release his tax returns, his plan to repeal the Affordable Care Act and his choice for education secretary, Betsy DeVos, who was confirmed despite deep opposition and skepticism about her qualifications for the post.

Many didn't like what they heard from the 81-year-old senator.

"Donald Trump is Donald Trump," Grassley told one man, who pressed him about how Congress can make the president more honest.

Tom Willett of Mason City, Iowa, confronts Grassley on the government taking funds from the social security surplus. 'A lot of us are counting on social security and Medicare,' he said. 'We don’t have that, we’re going to be in deep doo-doo, boss.' (Matt Kwong/CBC)

Grassley opened the session by polling the room for discussion suggestions.

"Respect for the truth!" a man shouted.

Someone demanded that Grassley "repudiate the lies" the president has been telling about subjects such as non-existent mass voter fraud.

"Save refugees!" came another voice, referencing Trump's immigration executive order.

Grassley managed a tight smile, gamely partaking in the political theatre that has been playing out this week across the U.S.

A group of liberal women on their way to attend Charles City town hall carry protest signs. (Matt Kwong/CBC)

With legislators returning home during a weeklong congressional recess, grassroots activists are commandeering the normally sparsely attended town halls. Opponents of the new government have been using the opportunity to confront them in sweaty fire halls, community centres and school gymnasiums, challenging their legislative representatives to hold Trump accountable.

In Minnesota, Congressman Tom Emmer threatened to cancel his town hall near St. Cloud if there was a "disruptive display."

In Arkansas, at least 1,000 people reportedly lined up to enter the high school auditorium where Senator Tom Cotton was holding court.

In Kentucky, Republican Senate majority leader Mitch McConnell was confronted by Rose Mudd Perkins, who spouted off about health insurance and a ravaged coal industry in a viral exchange.

Angry constituent gives Mitch McConnell the what for <a href="https://t.co/tyHseJVtqd">pic.twitter.com/tyHseJVtqd</a> —@BraddJaffy

And in Iowa, Thursday's Charles City crowd snaked down the hall and to the stairwell. An estimated 150 people crammed into the courtroom.

Dozens more waited outside, straining to hear Grassley's answers. Steve Juhl, an army veteran from Mason City, never got in. He intended to ask whether his senator supported earmarking a possible $20 billion US "so Trump can build a damn wall" bordering Mexico.

Inside the courtroom, one woman apparently touched a collective nerve when she criticized Trump's plans to revoke Obama-era environmental protections.

"Why is the GOP being so mean to its citizens and to this country, with its proposal to rape the Earth?" she demanded as the room erupted in applause.

"OK, now. Don't — don't all talk at once," Grassley said, breaking through the crosstalk.

The at-times rowdy back-and-forth went on for more than an hour in this rural community of 8,000.

Becky Higgins was verging on tears as she ripped into Grassley. 'Rural America is mad as heck that you aren’t listening to us,' she told him. (Matt Kwong/CBC)

Becky Higgins, on the verge of tears, said midwestern America was "mad as heck" at representatives she feels are too beholden to corporations and the new president.

Tom Willet accused Republicans of having their eyes on plundering the social security surplus.

But it wasn't a total Democratic hate-in, either. A man near the back defiantly wore his pro-Trump "Make America Great Again" ball cap, and Grassley won applause for defending Christianity against an atheist who described the U.S. under Republican leadership as an "American Taliban."

One Republican rose to say his Democratic fishing buddies reckon the whole town hall protest is a waste of time.

He was promptly shouted down.

Grassley, left, faces off with a town-hall attendee at the Floyd County Court House. (Matt Kwong/CBC)

To Iowa politics analyst David Yepsen, the activism bore some resemblance to the Tea Party outrage that stormed town halls and galvanized conservatives in 2009. At the very least, he sees the fun-house mirror image of that conservative movement.

Yepsen lists the familiar hallmarks: A new president viewed as a radical, talk of grassroots activism packing town halls, and once again, anxiety over a proposals to overhaul health care.

"The liberals are having their Tea Party moment right now," Yepsen says. "Something's happening here on the left. We don't have a label of it yet, but something on the left is energizing people."

Iowa became a red state in the November election, voting 51-42 per cent in favour of Trump — a flip from 2012 and 2008, when voters went blue for Democrat Barack Obama.

Steve Juhl, 65, an army veteran from Mason City, Iowa, was part of the overflow crowd unable to ask a question. 'I wanted to ask why in the world would you cut $20 billion out of the [Veterans Affairs] fund two and a half years ago, but now you want $20 billion so Trump can build a damn wall?' (Matt Kwong/CBC)

The left, Yepsen believes, is "embarrassed" by the 2016 outcome.

Grassley, whose long Senate career once drew comparisons to the state's sturdy bur oak trees, was now getting pulped.

"Grassley's not used to getting a rough time. Not like this," says Dennis Goldford, a political science professor at Drake University in Des Moines. The senator consistently wins elections by at least 64 per cent.

Conservatives have questioned the organic authenticity of the town hall protests. The White House suggested paid "professional protesters" are filling the rooms. Skeptics have taken to calling the movement "AstroTurf."

"Even if the current protests are grassroots rather than AstroTurf," Goldford says, "continuation requires organization and money. The Tea Party had those; we don't know whether the current activism does."

The about 150 town-hall attendees asked Grassley about U.S. President Donald Trump's first month in office. Similar scenes played out in counties across the U.S. this week during a weeklong congressional recess. (Matt Kwong/CBC)

At the courthouse in Charles City, Grassley appealed for calm. Whether liberals or conservatives, he addressed the audience, "I hope that you're going to be 'Iowa nice.'"

That didn't last long.

When Edith Haenel pressed Grassley on demanding Trump surrender his tax returns, another town hall attendee, John Kerby, glanced back to tell her to sit down and "shut up."

"She's being a pig," someone yelled.

Steve Tenney stood to remind Grassley he works for Iowans' interests in Washington, and must stand up to the administration.

'You work for us,' Charles City constituent Steve Tenney reminded Grassley during the town hall. 'We do respect you, but you’ve got to help us with this administration. Because you clearly know, you’ve never seen anything like this before.' (Matt Kwong/CBC)

"You're our representative, we need you to protect us," Tenney said.

To which Kerby heckled, "You can do it yourself!"

Blocks away on Main Street, conservative coffee-shop owner Bryan Elsbury didn't see what all the anti-Trump fuss was about. The 49-year-old Trump supporter likes the proposed Mexico border wall and travel ban. He believes in personal responsibility, and trusts the president will deliver on his pledges for a strong military and safe borders.

Elsbury says he's all for diversity, so long as it comes legally.

Bryan Elsbury, owner of Aromas Coffee on Main Street in Charles City, Iowa, is a vocal conservative supporter of U.S. President Donald Trump. 'I'm extraordinarily happy with what the president is doing, I'm all for it,' he says, calling the town-hall protests a 'manufactured' movement. (Matt Kwong/CBC)

"What's wrong with being patriotic to your country? What's wrong with asking people who come to your country to assimilate?"

Town halls, he feels, are little more than "pitiful" spectacles of partisan bickering.

Tell that to Grassley, the most senior Republican convening these meetings.

His 36-year Senate career was built on this kind of engagement, so much so that a "Full Grassley" is a well-known shorthand here for his annual pilgrimage to all 99 Iowa counties. (Of some dispute is how often he actually pulls this off.)

Conservative town hall attendee John Kerby shouted down a constituent who asked about Trump's tax returns. 'They do have a tendency to do sermons here,' he said later, questioning whether the meeting was productive. (Matt Kwong/CBC)

Whether Grassley drops in on meetings in all 99 counties depends on how much he'll be able to stomach. Hinting at the long combative road ahead, a hog farmer and Obamacare supporter in Iowa Falls earlier this week presented Grassley with a gift at another town hall, something to help with the expected stress — a bottle of Tums.

"You're gonna need 'em," the voter said.