President Barack Obama under mounting pressure as immigration legislation stalls.Jeff Topping

President Obama recently told immigration activists at a White House meeting that even if he wanted to halt the deportations of millions of illegal immigrants, he could not do so without congressional approval.

However, legal scholars are saying the president has more latitude than he lets on, and with increasing pressure to slow the pace of deportations from his Hispanic supporters the president has ordered his Homeland Security secretary to make immigration enforcement more humane, the Boston Globe reports.

The move has opened an intense debate about how far the president should go in protecting large groups of illegal immigrants from deportation.

On Friday, House Republican leaders intervened to prevent a vote on immigration legislation, a huge setback to efforts to overhaul the system.

In an interview on PBS’s “News Hour” last Thursday, Homeland Security Secretary Jeh Johnson said one of the policies under review is the program that allows Immigration and Customs Enforcement officials to run fingerprints of anyone booked for a local or state crime through a federal database for immigration violations and allows local police to detain the person if there is a match. The program could be changed to focus only on people who have been convicted of crimes.

But, according to the Boston Globe, these types of changes still fall short of the demands from most immigration activists, who want the concerns of the 11 million illegal immigrants in the country addressed.

Legal scholars say the president could follow through on proposals that would remove the fear of deportation and provide work permits for millions of illegal immigrants.

“Presidents have pretty much complete discretion when it comes to enforcing criminal and other statutory regimes,” said Peter J. Spiro, who teaches immigration law at Temple University. “Obama can’t start handing out green cards. Short of that, from a legal perspective, there are no serious constitutional or other legal constraints that apply.”

The president’s constraints are primarily political as any action to stop the deportations for millions of people would end hope of negotiating an immigration deal with Republicans. And a unilateral action by the president to waive deportations for large groups of people could lead Republicans to start impeachment proceedings. Republicans believe President Obama has already overstepped his constitutional authority with the changes he has made to his health care law and his State of the Union address in which he promised to use executive action to circumvent Congress.

However, with no obvious movement on immigration legislation, pressure is building for the president to do something.