Nobel Prize-winning economist Milton Friedman once said, “You cannot simultaneously have free immigration and a welfare state.” More recently, the Heritage Foundation’s Robert Rector, a laudable scholar in his own right, proved that Friedman’s claim is true. According to Rector’s exhaustive new report, released earlier this month, the net cost of first-generation amnesty will be $6.3 trillion.

Rector’s $6.3 trillion bottom-line number was produced by calculating the number of illegal immigrants who eventually would be eligible for the over 80 means-tested federal welfare programs if an amnesty were passed, and then calculating how much their use of those programs would cost taxpayers. He also factored in every tax and fee amnesty recipients might pay over their lifetimes: from tobacco excise taxes at the state level to federal income taxes. Rector did not include the cost of crime.

Rector found that the current population of illegal immigrants (and the next generation) will never be net contributors to the government’s coffers. Just 5 out of 12 illegal immigrants are currently working, and while that number might grow if they are legalized, they will never come close to paying into the system as much as they draw down. In fact, Rector estimates that they will fall short by $6.3 trillion. Eventually, that cost will drive the U.S. into a crippling debt crisis.

Six-point-three trillion dollars is a staggering number, but it was calculated using very reasonable assumptions. No one knows how many illegal immigrants are in this country, but the lowest estimate (barely above the number counted by the census) is 11.5 million — the number Rector used. In other words, $6.3 trillion is the floor, not the ceiling, for amnesty’s cost.

Rector’s unassailable method is the only holistic approach available to policymakers, and it would be irresponsible to ignore it in favor of approaches that consider only a few variables.

The study’s implications are profound. It raises questions not only about amnesty’s fiscal costs, but also about the origins of the amnesty proposal before Congress. Comprehensive immigration reform barely registered as an issue in the 2012 presidential election, but still some Republicans have chosen to run toward amnesty. They are obviously concerned more for their own re-election or future political aspirations than they are for the federal budget and the Rule of Law. They are making a political decision, not a decision based on sound policy.

Consider this: The Senate is holding hearings on a bill that will result in $9.4 trillion of new government spending (and $3.1 trillion in new revenue). Who will we spend this money on and what is their claim to that money? The single factor that puts illegal immigrants in a position to receive these handouts is the fact they violated the law. The only reason given by the legislation itself as to why we should open up our wallets, indebting our children beyond the conscionable, is that the illegal immigrants broke our laws. Their only claim to the same rights and entitlements afforded to Americans is their geographic location — which they came by illegally.

Since I arrived in Congress a decade ago, I have firmly supported the Rule of Law as a matter of principle. Rector’s research has allowed Congress to consider the real consequences of failing to stand on principle.

Friedman was right when he observed that a country can’t have open borders and a welfare state. Unlike during earlier waves of immigration, today the United States is a cradle-to-grave welfare state. If Congress passes what would likely be the largest amnesty in history, America will no longer be a shining city on a hill that inspires other nations to excellence, but 50 states with no hope of ever restoring the Rule of Law and a dramatically increased and empowered dependency class — the exact definition of the Obama constituency.

Rep. Steve King, a Republican from Iowa, is a member of the House Judiciary Subcommittee on Immigration Policy and Border Security.