In October 2013, Texas Republican Sen. Ted Cruz took a lot of criticism for his doomed effort to defund Obamacare. It was an impossible goal; the GOP was in the minority in the Senate and a Democrat was in the White House. Under those circumstances, defunding President Obama's signature achievement simply wasn't going to happen. Establishment Republicans were angry at Cruz for raising the hopes of the party's base before certain disappointment.

But there was one sense in which Cruz was right — and the words he spoke four years ago are resonating today in the GOP's struggle to repeal, or, more accurately, rewrite Obamacare.

Cruz based the defund effort on his contention that once Obamacare was fully in place and subsidies began to flow — that was scheduled to begin on January 1, 2014 — there would be no stopping it.

"The Obama strategy, I believe, is that on January 1, subsidies kick in," Cruz told a meeting of the Kingwood, Texas tea party in August, 2013. "And his strategy is very simple: He knows that in modern times no major entitlement has ever gone into effect and been unwound. Never been done. His strategy is to get as many Americans as possible hooked on the subsidies, addicted to the sugar."

"I think if we're going to stop Obamacare, we have to do it now," Cruz continued. "If we get to January 1, this thing is here forever."

Of course Republicans did not defund Obamacare — there was never any chance they could — and the subsidies began. And now, exactly as Cruz (and others) predicted, the entitlement program is proving extremely difficult to repeal. That is because, as Obama and the Democrats who passed it knew, Republicans trying to repeal Obamacare would be taking back something the government had already given to millions of Americans. Once the giving started, Cruz knew, there's no taking back.

And that's where Republicans are now. They've come up with a different way to provide subsidies, but regardless of name, they are trying to reduce those subsidies and make them available to fewer people. They are trying to cut back on the subsidized benefits insurance companies are required to provide to customers. They are trying to reduce the predicted number of people on Medicaid. They are trying to take back, not give. And it is proving very, very hard.

Other Republicans said similar things during the defunding battle back in 2013. Sen. Mike Lee said, "Before this law kicks in in full force on January 1, 2014, we have one last shot." Sen. Marco Rubio said, "This is our last chance and our last best chance to do something about this." Sen. David Vitter said, "Once [Obamacare] gets into law and starts to put down roots, it's going to be difficult to disrupt."

And now it is.

What the 2013 fight showed, and what the current fight is showing again, is that the Republicans' actual last chance to get rid of Obamacare was the 2012 election. That was before the health care law went into effect, before it touched millions of American lives, and when it could still be repealed without great disruption. But when Barack Obama won re-election and could safeguard (and prop up) Obamacare through its early years, the Republican chance to repeal was gone.

Now Republicans are fighting among themselves over a bill that would make substantial changes in Obamacare but leave the structure of the law intact. And several GOP lawmakers — enough to scuttle any final agreement — are afraid of cuts in subsidies, in coverage, and in the Medicaid expansion.

It all shows that Cruz was right back in 2013. Once Obamacare's subsidies and benefits began to flow, "this thing is here forever."