In a refreshing departure from earlier debates that bordered on the comic, Tuesday's faceoff among the leading GOP presidential contenders focused largely on important policy issues, with a blissfully modest moderator presence and some genuine moments where candidates attempted to hold one another accountable.

Bravo.

Now candidates must turn to the harder task: Laying on substance and heft to what have been remarkably thin proposals for an election that now looms less than one year away. Does that seem long? It's not. By February, the Iowa Caucus and the New Hampshire primary will begin their work of winnowing the field, and woe to voters if more substantive but less flashy candidates are the ones weeded out.

There is still much to be learned about how the contenders would handle taxes, spending, ISIL, trade, etc. But Tuesday night's debate did give the nation a glimpse of where it does not want to go on one critical question: immigration.

Donald Trump, who has made demonizing undocumented immigrants a signature issue, reached a new low in the debate, holding up as one example a 1950s deportation program set in motion by former President Dwight Eisenhower. "You don't get nicer. You don't get friendlier," Trump said of Eisenhower's approach. "We have no choice."

Those unfamiliar with this "nice," "friendly" program should know some of what Trump left out. For starters, it was called "Operation Wetback" — a brutal episode in American history that this country should not even contemplate repeating. The military-style action used planes, ships and trucks to forcibly deport tens of thousands of undocumented immigrants deep into the interior of Mexico.

Rounded up with little due process, forced to leave behind their belongings and unable to communicate with family members, these immigrants were left stranded, without sustenance or the means to return to far-off homes. Some died in the attempt. Others reported being beaten, jailed and even having their heads shaved by Border Patrol agents if they attempted to re-enter, as a way of marking them. Meanwhile American growers, still clamoring for low-wage workers, continued to recruit Mexican nationals to replace those taken.

John Kasich and Jeb Bush, who both have supported stricter border control along with a path to legal status for some, quickly called out Trump. In one of the most common-sense lines of the night, Kasich said of the nation's 11 million undocumented immigrants, "Come on, folks. We know you can't pick them up and ship them across the border. It's a silly argument. It's not an adult argument."

Marco Rubio, who has backtracked from the bipartisan immigration overhaul he helped write, now says that only a piecemeal approach can work. As the nation wrestles with this divisive issue that affects millions more beyond the immigrants themselves, along with major sectors of the economy, voters should demand detailed plans — devoid of button-punching rhetoric and glib applause lines — from both GOP and Democratic candidates.