Hillary Clinton pulled few punches in a fiery 25-minute address to the American Federation of Teachers in Downtown Pittsburgh mid-morning Friday.

Denouncing President Trump across a range of issues, she warned that “they are trying to rip the heart out of America. .. .They want to turn us against each other. They want to divide and conquer.”

Clinton, who lost the bitterly contested 2016 election to Trump, spoke even as federal prosecutors were unveiling charges against 12 Russians accused of hacking national Democrats in a bid to help Trump win.

But while she made a wry reference to the 10-year tenure of AFT president Randi Weingarten – “It never gets old, saying ‘Madame President,’” she joked – Clinton focused largely not on the election, but its aftermath.

She spoke harshly of Trump’s policies on a range of issues like immigration, which have featured immigrant children being taken from their parents at the border, with little apparent thought given to their reunification.

“The test of any society is how we treat the most vulnerable among us, particularly our youngest, our oldest, our people with disabilities," she said. "And right now, my friends, our country is failing that test. We have never seen such organized cruelty, disdain and contempt for those values.”

Speaking to an assembly that included teachers from the United States and 25 other countries, Clinton also called for opposition to the pending U.S. Supreme Court appointment of Brett Kavanaugh, who Trump has nominated to replace swing justice Anthony Kennedy. Kavanaugh is a staunch conservative whose fifth vote on the 9-member Supreme Court could overturn numerous legal precedents cherished by Democrats.

“This nomination holds out the threat of devastating consequences for workers’ rights, civil rights, LGBT rights, women’s rights, including those to make our own health decisions,” Clinton warned. “It is a blatant attempt by this administration … to reverse decades of progress.”

“I used to worry that that they wanted to turn the clock back to the 1950s. Now I worry that they want to turn it back to the 1850s,” she added. “These will be urgent fights.. … [E]verything that represents the progress we have made over the past 125 years, to make our country freer and fairer, to pursue the dream of a more perfect union, is at stake.”

Clinton urged teachers to educate their students and “keep standing up for the truth ... for evidence, for reason.” But she said voting in November was critical.

“I am worried about whether we will recognize America anymore. But we have a chance, come November, to make sure we get back on the right track,” she said. “If we take back one or both houses, which I pray we do, then we can start holding people accountable again, the way they should be. The alternative is too grim to think about.”

Clinton was on friendly ground, as scattered shouts of "We love you, Hillary!" attested.

The AFT, which boasts over 1.7 million members in education and health care nationwide, was an early supporter in the contested 2016 Democratic primary contest. So early, in fact, that union supporters of Bernie Sanders were upset at how quickly union leaders made their pick.

During her own speech prior to Clinton’s address, Weingarten seemed anxious to keep that in the past. She told members that in November, “We must be together, and we must be all in, which is why I am so glad that both Secretary Clinton and Senator Sanders are with us at this convention.”

On Saturday, another potential 2020 Democratic hopeful, Senator Elizabeth Warren, is expected to speak. Sanders is slated to speak at the convention on Sunday.

In addition to lambasting Trump with remarks of her own, Weingarten laid out a number of challenges facing the union.

She spoke at length about the U.S. Supreme Court’s ruling in the Janus case. A 5-4 court ruled last month that government unions could not collect dues from employees who opted out of the union. (Employees cannot be compelled to join a union, but because the union negotiates for benefits and working conditions, the court previously ruled that non-members could be charged for the cost of that representation.) The ruling is expected to weaken unions -- especially those who, like teachers, work in the public sector.

Weingarten decried the ruling repeatedly, calling it the work of a “right-wing” court majorty that “wants to destroy the aspirations and dreams of working folks.” But she also pledged the union would fight, boasting that its now counted 1,755,000 members – “the highest number ever.” Over a half-million members had “recommitted” to the union – agreeing to remain as members – since January, she said.

The AFT's Pittsburgh affiliate represents over 3,000 city school educators.

Like Clinton, Weingarten said the 2018 elections offer an almost existential choice for America at a time she called the “most crucial moment for American democracy since the rise of fascism and authoritarianism in the 1930s.”

“These elections won’t just determine whether Republicans or Democrats will prevail,” she added, “but whether cruelty or decency will prevail."