A system which "double-check on the candidate's validity, character and legal qualifications" exists in Iran. From wikipedia article on the Guadrian Council:
The Guardian Council of the Constitution is an appointed and constitutionally-mandated 12-member council that wields considerable power and influence in the Islamic Republic of Iran.
The Iranian constitution calls for the council to be composed of six Islamic faqihs (expert in Islamic Law), "conscious of the present needs and the issues of the day" to be selected by the Supreme Leader of Iran, and six jurists, "specializing in different areas of law, to be elected by the Majlis (the Iranian Parliament) from among the Muslim jurists nominated by the Head of the Judicial Power," (who, in turn, is also appointed by the supreme leader).
It is charged with interpreting the Constitution of Iran, supervising elections of, and approving of candidates to, the Assembly of Experts, the President and the Majlis, and "ensuring ... the compatibility of the legislation passed by the Islamic Consultative Assembly [i.e. Majlis] ... with the criteria of Islam and the Constitution". [...]
Since 1991, all candidates of parliamentary or presidential elections, as well as candidates for the Assembly of Experts, have to be qualified by the Guardian Council in order to run in the election. For major elections it typically disqualifies most candidates, for example in the 2009 election, 476 men and women applied to the Guardian Council to seek the presidency, and four were approved.
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