I know you're just quoting some random backlash, and that these dudes are just scoring free points, but I find it particularly ironic that most of those things would have or in fact did happen under the watch of a Republican admin. especially b/c there's a long list of valid stuff they could go after Obama for.
deal with a nuclear Iran? well, seeing as there's nothing we can do to stop them from obtaining nukes short of a full-scale invasion, presumably someone would've had to deal with a nuclear Iran sooner or later. tacitly or otherwise. (the right-wing response to Iran has a heady air of Canute & the sea about it)
throwing Israel overboard? its not difficult to argue that this is exactly what the policy of let Israel do what it wants presidents like GW & Reagan has done. let's see, when has Israel blundered all its worst FUBARs in the last 20 years. 1982, 1987, 2006. yep, all under Republican admins. meanwhile, by far the best progress made toward peace - Clinton.
Afghan in chaos? as mentioned, check.
I love how the U.N. is a ridiculous farce to conservatives until we let Russia & China veto our "significant actions" (like?) in the Security Council. then it's a real thing that we can't lose face at. meanwhile, they both have de facto real world veto power over plenty of stuff; I seem to remember Russia knocking around one of our supposed buddies in the Caucasus a little while back while GW sat on his hands and pretended not to notice.
& I especially love how post-WWII American dominance is not only natural, but something that's supposed to last forever, as if it makes any kind of sense that a nation w/~5% of the world pop. w/oceans on 2 sides would be able to control world affairs until the end of time.
there's just a loopy unreality to that whole worldview.