WASHINGTON, DC — Last fall, immigration advocates placed themselves under and in front of buses to stop them from shuttling immigrants to deportation hearings. Last week, Southern California protesters blocked buses carrying migrants who recently arrived in the country and were on their way to be processed.

Together they demonstrate how quickly the immigration front can shift, even as attempts to move an immigration overhaul through Congress drags on.

After numerous protests, fasting by activists on the National Mall, sit-ins and civil disobedience, immigration advocates have come up empty. The advocates’ demands for a hiatus on deportations have been pushed to the background by the arrival of tens of thousands of children, many on their own, and families on the Texas-Mexico border.

Sign up for breaking news alerts from NBC News

While President Barack Obama has said he would take action on immigration now that the GOP House has retreated from any action this year, he has repeatedly said the action he may take would be limited.

Erika Andiola, co-director of the DRM Action Coalition, said the administration has been asking advocates to lower their expectations of what the president will do by executive order.

Groups such as hers have issued declarations of support for the children crossing the border, as they continue to demand the president halt deportations on the more than 11 million immigrants here illegally.

“I can see why the children would come,” said Andiola, who is from Mexico. “Whatever you tell them is happening here, they are not going to choose leaving this country. We’re hoping that the administration is trying to find a way to keep them here safely.”

The children’s arrival has renewed Republican criticisms of Obama’s immigration policies and of GOP views that the border is not secure and therefore any talk of immigration reform is premature. Obama’s border security policies have included removing from the country people who recently cross into the U.S. and those who are caught re-entering after being previously removed.

When Congress returns from recess this week, the president will ask members for money to support agents, shift judges to the border and for other resources needed for authorities to start culling through the children’s and families’ cases.

Simon Rosenberg, president and founder of the New Democratic Network, said the current crisis could have serious impact on the president’s next steps on immigration and on Republicans’ response.

“The administration has to get its arms around the current crisis. Everything else that follows will depend on how well this is managed and how it goes.”

“The administration has to get its arms around the current crisis. Everything else that follows will depend on how well this is managed and how it goes,” Rosenberg said.

Getting it under control gives the administration more “running room” to take executive action on the deportations that have topped 2 million while Obama has been president, Rosenberg said. But he said Congress also needs to provide the money he’ll request because “there’s a limit to how much the president can do without Congress being a partner.”

“If they refuse to work with him, then they will be responsible for extending the crisis, creating additional human suffering and strengthening the (smuggling) cartels,” Rosenberg said.

Texas’ Gov. Rick Perry, a potential 2016 presidential candidate, made a similar appeal during a House Homeland Security Committee hearing in Texas Thursday. Perry told the House panel “the president really needs you on this issue.” Perry also told a House panel it is more humane to send the children back quickly.

Ali Noorani, who has worked to galvanize support for immigration reform from business people, evangelicals and law enforcement, said the crisis puts the border security ball back in the hands of House Republicans.

“As long as our immigration system is as chaotic as it is, cartels will continue to take advantage of it and sell lies to families,” Noorani said.

About 35,000 of the more than 52,000 unaccompanied children who have been taken into Border Patrol custody since Oct. 1 are from Central America. Homeland Security Secretary Jeh Johnson said on Meet the Press Sunday “our border is not open to illegal migration.” But he also said earlier that in addition to the violence driving children and families to the U.S., he believed smugglers have misled the migrants to believe the U.S. gives them permits to remain in the country once they get here.

Some children have been released to their parents or other guardians but also are given orders to show up for future deportation hearings. With backlogs in courts, many end up in the U.S. for extended periods awaiting hearings and others disappear into the U.S. interior. Alfonso Aguilar, executive director of the Latino Partnership for Conservative Principles, said Republicans are risking sounding heartless if they turn back the children to their countries, particularly if their parents are in the U.S.

“There’s a reason we don’t deport Central American children right away and the reason is we don’t know what is going to happen to them in those countries,” Aguilar said. “We are a compassionate nation.”

Daniel Vargas, a Republican political strategist, disagreed. He said the children have to be sent back. “We can’t absorb that many children in a lawless situation,” he said.

Regardless of the children’s arrivals, Vargas said any executive action taken by the president on deportations will decimate chances for immigration reform in 2015.