Hillary Clinton told a packed ballroom full of excited Democratic volunteers in Aurora on Tuesday that embattled U.S. Sen. Mark Udall was “fighting on the frontiers of freedom” by making women’s rights the centerpiece of his campaign against Republican challenger U.S. Rep. Cory Gardner.

Although Udall has taken heat for his campaign’s focus on Gardner’s varying positions on abortion and contraception — he’s been dubbed “Mark Uterus” by skeptical observers, a Denver Post reporter noted during a Senate debate earlier this month, and the Post’s endorsement of Gardner blasted Udall’s “obnoxious one-issue campaign” — Clinton pushed back against the criticism and urged volunteers to chase every vote in the tight race.

“As a woman and an American, I think it’s a big deal in this election,” said the former secretary of state and potential 2016 presidential candidate to roughly 1,000 supporters at the Radisson Denver Southeast. “This election is important for everybody, but it’s especially important for the women of Colorado.”

“I’ve heard, some may wonder why Mark Udall has stressed women’s rights in his campaign,” Clinton said. “I want you to understand that, as far as I’m concerned, and as far as Mark is concerned, when he’s fighting for women’s rights, he is fighting on the frontier of freedom. Because women’s rights, here at home and around the world, are clearly at risk unless people of goodwill, both women and men, regardless of political ideology, understand that women’s rights are like the canaries in the mine. If women’s rights are denied or rolled back anywhere, it is a threat to everyone’s rights everywhere.”

Clinton headlined the rally, held two weeks before ballots are counted, which also featured U.S. Sen. Michael Bennet, Gov. John Hickenlooper and former House Speaker Andrew Romanoff, who is hoping to unseat Republican U.S. Rep. Mike Coffman. It was the second time Clinton campaigned in Colorado in a little over a week, and campaign sources said her husband, former President Bill Clinton, was expected to rally Democrats in the state before the election.

While Clinton didn’t mention Gardner by name, she took aim directly at his shifting — and some say contradictory — stances on the personhood amendment, which would make abortion and some forms of birth control illegal.

“These Democrats will never support so-called personhood laws that would outlaw common forms of birth control,” she said. “They won’t tell the voters of Colorado one thing about personhood and tell their colleagues in the House of Representatives the exact opposite.” (Gardner withdrew his support from the state proposal soon after announcing his run this spring but has remained a co-sponsor of a federal version of the law, which would confer legal rights at the moment of fertilization.)

She also swung at another Gardner position, urging that the birth control pill be made available over-the-counter, and at his support for the Supreme Court’s Hobby Lobby decision, which allows employers to restrict which kinds of contraception their health care plans will pay for.

The right to abortion, Clinton said, “is under assault today across our country and is less secure than it has been at any time in the last 40 years. These Democrats will never shame and judge a woman for decisions that are complex and deeply personal,” decisions she said that should be between a woman, her family and her doctor, “not with her boss or a politician.”

As the crowd roared approval, she added, “These Democrats will never deny women health insurance for contraception and then tell them to just buy it over the counter, without even wishing them good luck in paying the bill.”

Udall stressed that the volunteers in the room – and thousands more across the state – would make the difference in a Senate race polls have shown to be in a virtual tie, with Gardner leading within the margin of error in several polls released in recent weeks.

“You all know this race is literally going to come down to the last ballot counted, but when the last ballot is counted, we’re going to come out on top,” he said. “You’ve all seen the polls, right? Ignore the polls,” he continued as the crowd laughed, if a bit nervously. “The poll on Election Day is the only poll that matters,” he added quickly. “This is the closest race in the country and control of the U.S. Senate hangs in the ballot.”

Introducing Romanoff, whom he beat in a divisive primary in the 2010 election, Bennet said, “Please welcome the hardest working person in show business.”The string of top-ticket Democrats stoked the crowd as they introduced each other, culminating in Clinton’s 25-minute speech.

A jocular Romanoff asked the crowd, “Are you ready to hear from the next president of the United States?” and then added, “Just in case she wants to make some news.”

“Is it just me, or does it seem like you’ve got to listen to a lot of guys before you get to hear the woman you’ve been waiting for?” Romanoff said to laughter.

Before bringing Hickenlooper to the stage, Romanoff thanked Bennet for his “hard work” advancing comprehensive immigration reform in the Senate and jabbed Coffman for his positions on the matter.

“I was a little surprised to learn that my opponent is now a big fan of that cause,” he said. “It’s true. I’d just read that Mike Coffman had met some immigrants — you can’t make this stuff up — and decided to retool his position.” As the crowd rocked with laughter, he continued. “If that is the new and improved Mike Coffman, I would hate to see what next year’s model looks like.”

Colorado Republicans ripped the Democrats for what the GOP termed “the last-minute deployment of Sen. Udall’s Washington friends to help rescue his troubled campaign,” calling the high-profile visits by liberal politicians “the actions of desperation, not confidence.”

“Sen. Udall is in trouble and that’s why he’s calling in as many of his friends from Washington as possible,” said GOP state chairman Ryan Call in a statement. “His fundraising over the past two weeks has been dismal. His performance in the debates was shockingly inept. And national reporters are picking up on what people in Colorado have known for months: that Senator Udall has failed us.”

Clinton also said how happy she was to welcome her grandchild into the world — “Charlotte!” someone yelled, and a delighted grandma responded that she was thrilled to let her granddaughter know she’d had her first shout-out — and pointed to a baby held aloft in the crowd.

“You think about the kind of future you want for your child and your grandchild,” she said, “and you think about what kind of state, country and world you want that child growing up in… What kind of opportunities are going to be around for the people that he or she grows up with?”

— Ernest@coloradostatesman.com