Immigration reform is having a “Kumbaya” moment, with support from the White House, a bipartisan contingent in Congress, business and labor.

The Republicans are petrified after their dismal showing among the fastest-growing slices of the electorate, Hispanics and Asians; President Barack Obama wants to reward the loyalty of those voters. Business and labor, as well as many politicians, want to fix a dysfunctional system. There are more than 11 million undocumented immigrants, 5 percent of the work force. Many of these people live in fear of discovery, while jobs go unfilled in some areas.

Hold the champagne. When it comes to immigration laws, the concept is always easier than the reality. Change failed to happen six years ago, even with a push from a high-powered coalition led by President George W. Bush and Senators John McCain and Edward M. Kennedy.

The dynamics are more favorable today. Still, the same obstacles persist; the powerful countervailing considerations include:

• A Pathway to Where? There’s a fairly broad consensus for ending the illegal status of the undocumented. The White House, Hispanic groups and most Senate supporters insist that any reform must lead to a pathway to citizenship.

That approach faces great resistance. Some lawmakers demand that any move toward citizenship must come second to solving the border-security problem, at a minimum. For some, this is a political cover; under the Obama administration, resources for border security have been increased sharply, including the use of drones. And deportations of undocumented immigrants are at a record high.

A border-security trigger is realistic if it includes quantifiable goals, such as the number of new Border Patrol agents, the amount of resources allocated and the new technologies utilized. It isn’t reasonable if it requires meeting an amorphous standard such as “operational control” of a border that is always changing.

Hispanic groups assert that the real motive for such demands is to unreasonably stretch out any possibility of granting citizenship.

“There would be a backlash if citizenship is delayed for 15 or 20 years,” warns Gary Segura, a Stanford University professor and co-founder of Latino Decisions, a research organization on Hispanic public opinion.

• A Fragile Coalition: Equally contentious is the question of future flows of immigrants. One proposal would link the number of legal immigrants to economic conditions: more would be let in when times are good, fewer in tougher times. That sounds easier than it is. There will be clashes over how great a priority should be given to those with high-tech skills or to agricultural workers or to family reunification. Small businesses will rebel against any costly verification plan.

Most independent studies show that immigration is a decided economic plus, bringing in revenue and increasing productivity and innovation.

Yet the arguments of the populist right may resonate more as the debate heats up. NumbersUSA, a leading anti-immigration group, is reviving charges that immigration reform would drive down wages for middle- and low-income workers. Kris Kobach, the Kansas secretary of state who authored anti-immigration measures in several states and the Republican Party’s platform position on the issue last summer, charges taxpayers would be hit with $2.6 trillion in added food stamp, Medicare and Medicaid and welfare costs. That estimate is refuted by reliable studies; it still cuts.