Alabama Sen. Jeff Sessions isn’t pleased with a proposed immigration bill that would clear the way for immigrant workers to enter the country.

“The Gang of Eight plan fails to live up to every major promise of its sponsors. There’s no border fence. There is no practical back taxes requirement. And illegal aliens will become eligible for every federal benefit, costing taxpayers trillions,” Sessions said. “It undermines enforcement and weakens our lawful immigration system.”

That’s why Sessions said he has filed amendments to the immigration bill.

“One particularly crucial amendment I have filed defends American workers,” Sessions said. “This bill would authorize a dramatic surge in permanent low-skill and chain migration—and would bring in millions more temporary foreign workers—at a time when 90 million Americans are outside the labor force and nearly 50 million are on food stamps. The result would be lower wages and more unemployment.”

Sessions’ amendment would cap the number of foreign workers granted admission to the country and immigrants granted legal status to about 30 million over a decade. Sessions said he’d like to see that number even lower, but it is a starting point in scaling back the bill.

Republican senators, including Sessions, have been voicing their opinions that they don’t believe border security is strong enough in the bill despite the allocation of about $5.5 billion for border measures that would include 100 percent surveillance of the entire border and blockage of about 90 percent of border crossers in high-entrance areas.

Now, a study released by the Heritage Foundation has set off another dispute between conservatives and more liberal senate members. The study found that the immigration bill would cost the government about $6.3 trillion over then next 50 years to provide benefits for millions of people now living in the United States illegally.

The conservative think tank said that immigrants granted legal status under the bill would cost the nation more than $9 trillion in health, education, retirement and benefits over their lifetime, while only contributing about $3 trillion in taxes.

Proponents of the bill said they don’t take the study seriously and said it was a political scare tactic.

Sessions said, he feels the bill is going to have a hard time making it through both the House and Senate, as-is.

“Already, one of the bill’s chief sponsors has admitted it will have trouble in the Senate and can’t pass the House,” Sessions said. “If even the modest amendment I have offered fails, it is exceedingly difficult to see a way forward for this bill. There is simply no public support for a tripling of the immigration flow into this country as this legislation calls for.”

The Associated Press contributed to this report.