First of all, let's be clear that Cruz is not "on Obamacare." There is no such thing as being "on Obamacare." It's not an insurance plan, or a single program like Medicare or Social Security. Cruz, Rubio, Ryan, Paul, and the 11.7 million other Americans who have used the exchanges are all on private insurance plans, and there are hundreds of them to choose from.
But that's about where the similarities end. Cruz—and Rubio and Ryan and all the rest of lawmakers in the exchanges—aren't really using Obamacare for any of the reasons it exists, or in the same way the other 11-odd million enrollees are.
Most Americans, about 60 percent, get insurance through their jobs. The exchanges are there for people who don't, and therefore have to buy it on their own.
The Cruz family was among the 60 percent of people who get insurance through work. They used to covered by the plan offered by Heidi Cruz's company, Goldman Sachs. But she is taking an unpaid leave for the presidential campaign, so they're switching to the coverage offered by Ted Cruz's employer—the federal government.
And if members of Congress want to get health insurance from their employer, the Obamacare exchange in D.C. is the first place to go.
Members of Congress used to get their health insurance just like any other federal employees, but Obamacare changed that. An amendment from Republican Sen. Charles Grassley kicked lawmakers and their staffers out of the exchange for federal employees; instead, they would have to use an Obamacare exchange. The government can still cover a portion of their premiums, just as almost all large employers do for their employees.
If he really wants to make a point, Cruz can go outside the exchange. But he probably would be purchasing roughly the same coverage—maybe even the exact same policy, just using a more cumbersome shopping process.
The biggest reason for lawmakers to use the exchanges, though, is so the government will be able to make its contribution to their premiums. Cruz has said he will forgo that subsidy, which would have covered more than 70 percent of his family's premiums.
The subsidy that Cruz passed up—but that other lawmakers are receiving—is not from Obamacare. It's from his job, and it's very common. Americans who have employer-based insurance (remember, that's about 60 percent of the country) get, on average, 70 to 80 percent of their premiums paid by their employers, according to the Kaiser Family Foundation.
So, sure, Ted Cruz might go into the exchanges. With most members of Congress. And even if he had taken the government's contribution, that would have been a standard workplace benefit unconnected to the Affordable Care Act.
This whole process is an aberration. It's not an extension of how Obamacare works or what Obamacare does.
Congress shoehorned itself into the exchanges to make a political point ("what's good enough for our constituents is good enough for us"). The Obamacare safety net is not catching Ted Cruz, nor is he surreptitiously hoarding the particular benefits he wants to take away from other people. This is just the awkward process that Congress decided on.