That wasn't the question though. It had to do with choosing a moderate over the number of strong conservatives running and why that is.
Don't be dense!
There was a full primary campaign with each candidate fully vetted. There were no rules that only conservatives could vote, or only moderates could vote. The reason why Romney won is simple, he was not distracted by democrat bait. It's the economy, he stayed there and sat on the issue as if it was an egg. Then it hatched into the nomination. Democrats are prejudiced. They have prejudged and formulated the "average" republican voter, imbuded that voter with democrat picked interests, and attributed the whole construct to the republican primary. If democrats need to ask why a moderate was chosen over the strong conservatives, it means democrats haven't got a clue as to the process. Likely, since human republicans are far more complex than human democrats the strong conservative candidates were rejected for reasons having nothing whatsoever to do with conservative values.
Of all the republican candidates running, only Romney recognized that the bait the democrats threw out was maggoty. The war on women, the war on dogs, the endless social issues that democrats dragged around like Achilles dragging the body of Hector around the walls of Troy. They were all distractions. Romney never bit, nor did he even nibble. Santorum did, not only did he bite, but he flashed a bit of anger when he realized that he couldn't stop the democrat lies. Gingrich became too personally involved and ended up disliked. Cain was deliberately attacked and taken out by a string of democrat operatives.
This particular election is not about social values. Social values are a luxury when things are going pretty good. This election is about the economy and the mess obama made of foreign policy. Democrats want to force the election into being about social policy, it won't work because the Republican candidate is Mitt Romney. That's why he's the nominee and not a more conservative candidate.