You may think this refers to all of the GOP being crap. Or if elected how all of them would do a shitty job. No actually the Stoolometer refers to what is called the Three Legs of Conservative Stool. Since the mid-70’s, when the modern conservative movement really was cemented and began really taking over the GOP and American politics, many have said that it was a three-legged stool. One leg being economic conservatives (balance the budget, deregulate and cut taxes), a second being foreign policy conservatives (big military spending, confront the Soviets and now the war on terrorism [aka islamo-fascism on planet Horowitz]), and lastly social conservatives (ban abortion and gay marriage, no gun control).
Over the years the GOP tended to nominate people who satisfied all three legs, even if they were much stronger in one leg than the other two. For example, John McCain supported tax cuts and would ban abortion but it was his strong foreign policy credentials that convinced enough Republicans to look past his transgressions and nominate him (or another way of looking it is to be the one to be left holding the bag for the Bush years).
So we should look at all of the candidates and measure just how well the rank in satisfying all three legs of the stool.
And of course is satisfying these three legs a good idea? After all the world has changed a little since the days of ERA, Kemp-Roth, and the USSR.