I want to know about the fact that certain positions seem to be tied to ideology which is in turn tied to partisanship. For example, the issue of gun control. Supporting gun control is strongly tied with being a liberal Democrat and opposing it is tied with being a conservative Republican. I have noticed that with websites and how positions fall ideologically. Is the fact that certain positions are proxies for other positions on issues that may not be related a new phenomenon?
If I understand the question correctly, it is about ideological coherence or consitency. The more ideologically coherent the base of a party is, the more thoroughly its followers will agree on a list of ideological issues. Issues like gun control and, say, abortion or deficits are superficially unrelated but ideologically connected. On the one hand, the party system has always implied a degree of ideological coherence. However, yes, this has been increasing for some time due to partisan polarization. Here's a helpful bit from Pew Center on this.