The issue of immigration has played a central role in the presidential race, particularly on the Republican side. Among the three top remaining GOP contenders, frontrunner Donald Trump has advocated a temporary ban on all Muslims seeking to enter the United States. and proposed revoking the Constitution’s guarantee of birthright citizenship, while perhaps the biggest concern among Republican primary voters regarding Sen. Marco Rubio (R-FL) is his 2013 support for a pathway to citizenship for undocumented immigrants.

Sen. Ted Cruz (R-TX), an immigration hardliner, has sponsored two main bills this session to address the issue of undocumented immigrants. S. 2193, Kate’s Law, and S. 1762, the Establishing Mandatory Minimums for Illegal Reentry Act — with only slight variations between the two — would both essentially do the same thing: increase penalties for those who illegally re-enter the country after being removed.

The former was introduced by Cruz in July alongside its House counterpart introduced by Rep. Matt Salmon (R-AZ5). For anybody caught re-entering or attempting to re-enter the country after being deported at least three times, the bill would stiffen the penalty to a minimum five year sentence if the individual had previously been convicted for an aggravated felony, up to 20 years.

Kate Steinle, a San Francisco woman appeared to be killed at random in 2015

The legislation was inspired by and named after Kate Steinle, a San Francisco woman appeared to be killed at random in 2015 by a Mexican citizen who had been deported five times with seven felony convictions. Conservatives have seized upon the story as an anecdote with which to promote their immigration policies, including ending the practice of so-called “sanctuary cities” that don’t notify U.S. Immigrations and Customs Enforcement before releasing detained undocumented immigrants. There are about 340 such cities, including San Francisco.

Cruz’s bill was introduced on October 21, intended as a substitute one day after the Senate voted down a similar version introduced by Sen. David Vitter (R-LA). S. 2146, the Stop Sanctuary Policies and Protect Americans Act, actually received more yes votes than no votes, with 54 supporting, but that still failed to meet the 60-vote threshold required to pass cloture.

“When it comes to stopping sanctuary cities and protecting our safety, we need some governing. We need to actually fix the problem,” Cruz said. “This ought to be a clear choice: With whom do you stand? I hope my colleagues in the Senate will support this bill and stand with the American people — the people we should be protecting — rather than convicted felons like the murderer of Kate Steinle.”

The White House has issued a veto threat for this type of legislation.

“The bill would essentially turn State and local law enforcement into Federal immigration law enforcement officials, in certain circumstances,” the White House wrote. “The Administration believes that these provisions would lead to mistrust between communities and State and local law enforcement agencies; undermine the ability of law enforcement to keep communities safe across the country; and impede our efforts to safely, fairly, and effectively enforce the Nation’s immigration laws.”

The American Civil Liberties Union estimated the bill would cost $3.7 billion over the next decade. Also, some voices on the right (though usually drowned out) have argued that it could undercut the recent push by conservatives for lessening or eliminating the “mandatory minimums” used in sentencing.