Former Pennsylvania Sen. Rick Santorum went further, calling for a 25 percent reduction of low-skilled immigrants coming into the country legally.
    "Everyone else is dancing around it. I'm going to stand for the American worker," Santorum declared.
    Monday's participants included seven current or former governors, four senators, a businesswoman, a retired neurosurgeon and one former senator. Trump, who launched his presidential bid by calling Mexican immigrants rapists and criminals, was among only three major candidates who didn't participate.
    Monday's event was broadcast live on C-SPAN and local television stations in Iowa and South Carolina — states that, along with New Hampshire, will host the first contests in the presidential primary calendar next February.
    Just an hour before the forum began, the Senate blocked a GOP-backed bill to strip funding from Planned Parenthood, reviving a debate on social issues that some Republican officials hoped to avoid in 2016.
    Three of the four senators participating in Monday's event —Marco Rubio of Florida, Ted Cruz of Texas and Rand Paul of Kentucky — did so via satellite from C-SPAN's Washington studio so they wouldn't miss the high-profile vote.
    "We had to be here to vote to de-fund Planned Parenthood," Cruz said.
    It's a welcome debate for Democrats who see women — married women, particularly — as a key constituency in 2016. Leading Democratic presidential candidate Hillary Rodham Clinton, who would be the nation's first female president, lashed out at the attacks on Planned Parenthood in a web video released before the GOP forum.
    "If this feels like a full-on assault for women's health, that's because it is," Clinton said in the video, criticizing by name former Florida Gov. Jeb Bush, Wisconsin Gov. Scott Walker and Perry.
    Democrats are also eager to debate Republicans on immigration.
    GOP leaders have acknowledged the need to improve the party's standing among Hispanic voters. Yet while many Democrats favor a more forgiving policy that would allow immigrants in the country illegally a pathway to citizenship, most Republicans in the field instead focus on border security.
    Rubio, once a lead salesman for a comprehensive immigration overhaul, said Americans want the border fence completed and more border security agents before there's any discussion of what to do with those 11 million immigrants in the country illegally.
    Others offered a softer tone. Ohio Gov. John Kasich said "law-abiding, God-fearing" immigrants should be allowed to stay. Those who break the law, he said, "have to be deported or put in prison."
    Bush said fixing the nation's immigration system is a key part of his plan to help the economy grow 4 percent each year. He also called for reducing legal immigration, particularly the number of people allowed to enter the country to rejoin family.
    President Barack Obama injected another contentious issue Monday when he unveiled new emissions limits on power plants designed to address climate change. He called it a moral obligation and warned anew that climate change will threaten future generations if left unchecked.
    Wisconsin Gov. Scott Walker called the move "a buzz saw to the nation's economy."
    "I want to balance a sustainable environment with a sustainable economy," Walker said.
    Several candidates involved Monday night won't make the cut for Thursday's debate. Those on the bubble include South Carolina Sen. Lindsey Graham and former technology executive Carly Fiorina, who charged that Clinton has repeatedly lied during investigations into her use of a private email server and an attack on an American embassy in Libya while she was secretary of state.
    "These go to the core of her character," Fiorina said.
    After the debate, Kasich was asked about Trump's absence.
    "I never thought about him," the Ohio governor said. "It'd have been great if he'd have been here."