Republican Sens. Ted Cruz (Tex.) and Rand Paul (Ky.) are two of the tea party's biggest heroes. They're often lumped together as leaders of a stridently conservative movement that is regularly at odds with the GOP establishment.

But not all tea party rock stars are created equal.

Sen. Ted Cruz (R-Tex.). (Senate TV via AP)

In separate media interviews broadcast Sunday, the two Republicans showed where they part ways in both style and substance, offering a glimpse at potential battle lines in the 2016 GOP presidential primary.

Cruz does not feel like he is aligned with Paul on foreign policy. He made that point in no uncertain terms.

"I'm a big fan of Rand Paul; he and I are good friends. I don't agree with him on foreign policy," Cruz told ABC's "This Week With George Stephanopoulos." "I think U.S. leadership is critical in the world, and I agree with him that we should be very reluctant to deploy military force abroad, but I think there is a vital role, just as Ronald Reagan did."

Paul is well-known for his libertarian-leaning views on foreign policy and national security. But Cruz has made clear that's not where he comes down. He described his approach last year as "somewhere in between" Paul and hawkish Sen. John McCain (R-Ariz.). (Side note: doesn't just about every Republican fall in between those two poles?)

The Kentucky senator has continued his crusade against government surveillance and has sounded notes of caution about intervening abroad. But he defended himself Sunday against critics who contend he is too soft.

"I think those who would try to argue that somehow I'm different than the mainstream Republican opinion are people who want to take advantage for their own personal political gain," said Paul on "Fox New Sunday." "I'm a great believer in Ronald Reagan. I'm a great believer in a strong national defense. In fact, what Ronald Reagan said in about one sentence sums up really a lot of what I believe."

(Second side note: Both Paul and Cruz both invoked Reagan.)

Foreign policy is not the only area in which Paul and Cruz differ. Another distinction has to do with political rhetoric.

In his speech at the Conservative Political Action Conference last week, Cruz knocked three recent GOP presidential nominees as evidence that abandoning conservative principles is a losing proposition.

"We all remember President Dole, President McCain and President Romney," said Cruz, who notably praised Ron Paul, Rand Paul's father.

Paul's reaction? Not the way I do things.

"I would just say that everybody has their own style. My style is that I stand for things, and I don't think -- people don't question whether I stand for principle. But I don't spend a lot of time trying to drag people down," said Paul.

Both Paul and Cruz are possible 2016 presidential candidates, which raises the question: What do these difference mean for 2012? The answer is they are more evidence the primary will probably be a complicated race in which it will be hard to put the candidates into any one box.

Yes, Cruz and Paul would in many ways be the "tea party candidates." But as Sunday showed, that hardly tells the whole story. Meanwhile, New Jersey Gov. Chris Christie (R) has clashed with Paul over foreign policy. But that does not mean he will clash with Cruz over the same topic.

As we've written, candidates are quickly starting to define their lanes ahead of 2016. But those lanes are simply not as clear cut as they might seem.