The Senate bill, originally drafted by a bipartisan group of senators called the Gang of 8 in mid-April, is controversial for some because it would open a pathway to citizenship for the 11 million undocumented immigrants currently in the country. Some view that as amnesty.
"The amnesty will occur, but the enforcement is not going to occur, and the policies for future immigration are not serving the national interest," said Sen. Jeff Sessions (R-Ala.), who has emerged as a chief opponent of the bill.
The border security amendment, by Sens. John Hoeven (R-N.D.), and Bob Corker (R-Tenn.), which requires a doubling of border patrol agents, fencing, drones and sensors, was officially added to the legislation Wednesday.
"The path to actually making a law is fairly clear at this point. Success on immigration reform runs through the border," McConnell said on the Senate floor.
The border security measures added in the amendment would be "triggers" that would have to be achieved before citizenship for the 11 million undocumented immigrants could be granted.
The Congressional Budget Office announced last week that the legislation would boost the economy by increasing the Gross Domestic Product by 3.3 percent by the year 2023, and by 5.4 percent by 2033. The CBO said it would also lower the federal deficit by $197 billion over the first 10 years, and $700 billion over the next 20 years.