We should be critical of all candidates, especially our own. I criticize them all. Ron has the fewest complaints across all issues, but no candidate should be 100%. Criticism has become unPC in the modern english lexicon - all it means is to rationally evaluate. Please, by all means criticize Paul, but do the same to Gingrich, Romney, Santorum, et al.
If you are solely voting on the basis of electability, then you are not thinking critically about your candidates. You are just voting in fear of Obama. I have compared all the GOP candidates side-by-side on all the issues, criticizing each one's views with the information readily available on the net. They have been weighed, they have been measured, and Ron Paul is the least wanting of them all ... particularly on the 2A.
Ron Paul has an A rating from the NRA, and his voting record is strong. He opposed any legislation enumerating federal powers over gun ownership, sales, manufacturing, transfer or operation. He proposed legislation taking those powers away from municipalities that overstepped their bounds. He has supported the individual right under the 2A, and stated that the militia was not the national guard, but communities and families who had need to cooperate and found self-regulation to be appropriate to their need. He has supported right to carry, noting that requiring a firearm to be locked up unloaded in your home, separate from ammo, is infringement as the 2A is a right to defend one's liberty with arms.
Romney is an anti-gun progressive liberal who joined the NRA in 2007 to win Republican votes. If you vote for him because you think he'll beat Obama, you are voting against the 2A. His policies are right in line with Obama.
Newt has flip-flopped, making bold statements, but supports legislation that enumerates federal power over firearms. He's only stronger on gun rights in comparison to Romney and Obama, but that's not saying much. While a life time member of the NRA, he is considered by other 2A organizations to be an anti-gunner based on his voting record. He seems to use the issue against others, but his own stance is soft. Don't expect any current or pending 2A infringement legislation to be vetoed by him; his record is to walk the middle.