Most liberals and many economic conservatives argued that support for such legislation was a political imperative for Republicans. Otherwise, they would continue to lose Hispanic voters, an inevitably increasing segment of the electorate, by 2-1 margins.
That argument was bolstered by the 2004 exit poll, which showed comprehensive immigration supporter George W. Bush getting 44 percent of the Hispanic vote. That percentage may have been inflated, but if Bush had received the percentages of John McCain (31) or Mitt Romney (27), he would probably not have been re-elected.
Republican opponents of comprehensive immigration respond that granting citizenship to illegals would enfranchise millions of Hispanics who would vote heavily Democratic on economic issues.
And they argued that a nation based on the rule of law should not reward lawbreakers. On that basis most Republicans voted against the comprehensive bill co-sponsored by Chuck Schumer and Marco Rubio that passed the Senate in June 2013.
Meanwhile, as the politicians debated, the facts on the ground changed. Net migration from Mexico, the source of more than one-third of all immigrants and about 60 percent of illegals from 1982 to 2007, fell to zero after that.
And polls showed that most Americans favored legalization of the so-called Dreamers, young adults whose parents had brought them illegally across the border when they were children.
Barack Obama, who didn't push immigration legislation when Democrats had Congressional supermajorities in 2009-10, announced he would no longer deport Dreamers who met certain conditions. As on many other issues, he was not troubled by the fact that the Constitution gives the task of passing laws to Congress and requires the president only to faithfully execute them.
That didn't seem to have any political downside. But the facts on the ground changed again. According to the Obama administration, only 4,000 unaccompanied minors approached the border in fiscal year 2011. That rose to 21,000 in fiscal year 2013 and to 47,000 in fiscal year 2014.
Almost all seem to have come overland through Mexico from the Central American republics of Guatemala, Honduras and El Salvador. Reports of this unanticipated surge have been filling television screens.
Instead of being sent back across the border, they have been housed in jammed facilities under the Deferred Action for Childhood Arrivals policy. Some have been given bus tickets to relatives in the United States, according to CNN.
News of this unexpected surge of illegal immigration seems to have contributed to the surprise defeat of House Majority Leader Eric Cantor in the June 13 Virginia Republican primary.
And last Friday the administration dispatched Joe Biden on a previously unscheduled trip to Guatemala to tell people there that, "there is no light at the end of the tunnel."
Liberals have argued that these teenagers are fleeing the high rates of crime and violence in their native countries. The implication is that they should be admitted as refugees from oppression.
But there's good reason to believe that many have come to believe that they have permisos to enter and remain in the United States. Once you announce you refuse to enforce one law, people may conclude you won't enforce others either.
The Cantor defeat and the surge of Central American teens make it unlikely that House Republican leaders will advance much in the way of immigration legislation.
Two trends in polling also point in this direction. One is that Hispanic voters don't seem hugely preoccupied with immigration. The Pew Research Center reports that many more focus on education, the economy and health than the one-third who say immigration is "extremely important" to them personally.
The other is that the president's job approval among Hispanics has been falling sharply. He got 71 percent of their votes in 2012, but fewer than half approve his performance today.
It's not hard to see why. The sluggish economy has hurt Hispanics more than most Americans. Obamacare and big government policies have not helped them as they apparently have hoped.
This suggests that non-passage of comprehensive legislation won't hurt Republicans as much as predicted. And inaction, always the easier legislative course, would prevent a debate in which the cries of angry opponents, gleefully highlighted in mainstream media, could antagonize Hispanic voters.