President Obama�??s amnesty plan may be costly to the U.S. economy, but it�??s big business for conservative grassroots groups fighting the unprecedented executive decree.

�??This is big,�?� said Roy Beck, executive director of NumbersUSA, the nation�??s largest grassroots immigration-reduction organization.

The Arlington, Va.-based nonprofit boasts membership, including Facebook followers and recipients of the organization�??s email newsletters, of north of 3 million individuals.

Since word came down that Obama would bypass Congress and issue an executive order that would provide temporary legal status and work permits for nearly half of the nation�??s illegal immigrants �?? around 5 million �?? NumbersUSA has seen its Facebook engagement rate soar. An engagement rate is the percentage of people who saw a post and liked it, shared it, clicked or commented on it.

And the group�??s fundraising numbers have exploded in recent days, according to Beck. Small donations are on the rise, as they often are in times of high-profile immigration issues.

�??But we are really pulling in some bigger donations right now,�?� Beck said. �??Folks are really paying attention to their tax deductions, giving the big money. They�??re saying there is an awful lot on the line.

�??People are legitimately concerned about the whole state of our constitutional government,�?� he said. �??This is not around the edges, this is right in the heart of America.�?�

The president shrugged off the label of �??amnesty,�?� asserting in his speech Thursday night that amnesty is the broken U.S. immigration system in place, �??millions of people who live here without paying their taxes or playing by the rules, while politicians use the issue to scare people and whip up votes at election time.�?�

It�??s amnesty, critics contend, when legal status is afforded to millions of illegal immigrants while so many millions who played by the rules spent so long in the pursuit of U.S. citizenship. Obama says his order will not provide a pathway to citizenship and does not open the door to federal benefits such as Obamacare.

Policy experts are arguing those points, with some saying the amnesty order could cost taxpayers untold billions of dollars in public assistance.

And, there�??s a lot of outrage out there. Chuck Molyneaux, a member of the McKinney (Texas) Tea Party, said he has heard plenty of it in the past couple of days.

�??This is an extremely strong driving point in the conservative movement across the United States, particularly in the South,�?� he said of the amnesty order. �??It�??s huge. The ramifications of this are disastrous.�?�

Molyneaux said his organization has seen emails spike since Wednesday, when the president first announced his intentions to be a one-man immigration reformer.

James Neighbors, founder and president of Overpasses for America, a limited-government organization that originally formed as a movement to impeach Obama, said the activity level on the group�??s website, email communications and phone communications has �??skyrocketed�?� since Wednesday.

�??And it�??s increased across the board,�?� he said. �??This is something that is very important to the American people, and the overwhelming message I�??m getting is that there is no need for reform, there is need for enforcement. �??

Neighbors said he was leaving Thursday night for Las Vegas, where a group of anti-amnesty movement members plans to protest Obama�??s order-signing ceremony Friday. The event is expected to be held at the Las Vegas high school where Obama rolled out his original immigration reform vision in 2012. His �??deferred action�?� plan retains many of the same features.

Beck, of NumbersUSA, said he has seen spikes in engagement and contributions during past immigration battles in Congress, but this battle, he said, is different. There�??s much more at stake, and he believes many more will join the fight in the coming weeks.

�??I think this is going to go on for some time,�?� he said. �??Some people say we may be fighting this for the entire final two years of Obama�??s presidency.�?�