The United States doesn't have compulsory voting like Turkey does. Australia, another country with compulsory voting (although much better enforced), regularly sees elections with over 90-95% turnout. That is a real democratic mandate.

Thanks for the information; I was unaware that Turkey has compulsory voting.

Is there a credible opposition party to AKP, or a smattering of smaller parties?

There is a long list of opposition parties in Turkey but few of them have any power [1]. The main opposition party with about a quarter of MPs (vast majority representing urban districts) is the Republican People's Party, which was the first political party in Turkey post WWI as well as the one led by Ataturk during his secular revolution.

[1] https://en.wikipedia.org/wiki/List_of_political_parties_in_T...