I disagree. It is one item but others matter just as much.
read the link - it tells why the gun issue is the view straight into the belief system of the politician.
I bet your other issues will correlate nearly 100% with this one issue.
Taxes - trust the individual or the government
Property rights - ditto
social programs - ditto
and, oh, the abortion issue - the unborn baby IS an individual human, so, ditto above.