It's a split.
Broadly speaking, the Republican party is really a coalition of two conservative groups, but two very different, almost diametrically opposed conservative groups.
You have the "fiscal conservatives" who think everybody should be hands off anything economically. This is the "free markets" Republican you tend to think of.
Then you have the "social conservative" who think everyone should be righteous and whatnot. They want not only themselves to be righteous, but you as well. To force you to live by a religious code that you don't follow, you sometimes need government interference. The joke being here "the Republican party wants government so small it just sleeps in bed with you and tells you No."
These groups were kind of glued together in the Nixon years, and really cemented in the Reagan years, It kind of explains some of the multiple-personality-disorderness of the current Republican Party. I'm surprised it hasn't blown up yet - do you really think a true Tea Partyer has much to talk to Rand Paul about? The doggedness of corralling "rogue" Republicans and painting them as R.I.N.O kind of keeps this all together.
That being said, many supposed fiscal conservatives really aren't so much. "Fiscal Conservative" Sarah Palin bloated a small city's spending so much she sent it into a debt spiral. The largest recent expansion of government was under Bush #43. Before that? Reagan. Wasn't the quote "Reagan proved deficits don't matter" - not very fiscally conservative. "Tax and spend" Clinton ran a fiscally responsible government and ran a surplus (which goes into the above - Bush had cash to burn, and so he did). Paul Ryan wants to gut government programs, yet he wouldn't be where he is today without them - he kind of skirted on Social Security benefits to get through college. Fiscal Conservative makes a great bumper sticker, but many Republicans seem to live by "please let everyone be fiscally conservative, well everyone but me".