Support! I do not participate in US elections, yet my homecountry definitely needs this too.
Democracy of incompetent voters is doomed to fall into dictatorship at one point.

To function properly, a democracy needs a well-informed electorate. The 2016 election patently demonstrates that this is not the case in America. I support your proposal in theory, although we would no longer be able to call our system democratic if not everyone had equal opportunity to obtain the education to pass the exam. You would absolutely see fewer voters from lower socioeconomic strata if you implemented this now. Until that is accounted for....

Be an American citizen. Qualifications not being honored by either party: 1) voter must be alive, and votes not submitted in the name of the deceased; 2) voter must have proof of citizenship; 3) voter can only vote once at the assigned precinct. Oh...and hey...how about going back to the manual voting style? The electronic machines are a fraudulent joke.

Name your current US Senators.
Name your Congressional Rep.
Name the Governor
Name the Vice President
...seems that would weed out some..

Agreed... would also like to have a law insuring campaign promises are kept, or a damn good reason why not.
As mentioned in previous comments, minimum requirement for candidates, such as, working knowledge of US Constitution, working knowledge of governing, of law, with NO influence from Citizens United. ... I’m just dreaming...

You won't have many left je pense

In theory, democracy is not the rule of the majority of a mob, but the wise decision reached by informed citizens. In practice a large part of those who vote is indistinguishable from a mob, easily manipulated by spin doctors and advertisement experts who use click-bait and attention whoring to manipulate opinions.
So in theory, a competency exam sounds like a good idea: before somebody votes they should probably know about the political system, the institutions and at least the basics of the laws and regulations proposed etc.
The problem is that in practice, the exam will immediately be abused to skew voting in favour of some of the powers and even if not, there will be the accusation that this is the case. There is no practical way to do this, so our only hope is the basic education everyone should get in a civilised country. If we look at the current state of affairs, doesn't look too good on that front either.
But in case, in practise there appears to be no alternative to the free and universal ability to vote for every citizen in a democracy

I want people to vote for a de-identified questionnaire. You don't pick a candidate, you pick a person who answered 10-100 questions the way you wanted. That'd remove so much money from politics and weed out retarded votes...

politicians should sit a public exam and prove competence before they can be in any position of power way to many stupid people running countries

That sounds a little like anti-voter legislation. What’s next? Voter legislation based on skin color?

Here in the UK, this would be very simple to achieve. All you'd have to do is replace the people who hand out the voting slips at the polling station with a computer running a small program asking them which newspaper they read. If they answer the Daily Mail, The Sun, the Daily Telegraph or The Star, the computer does not print a voting slip and advises the would-be voter that they are ineligible.

(Note to non-UK people: the Daily Mail, Sun, Telegraph and Star are the sort of newspapers you can't even use as toilet paper because you'd wipe more on than off.)

If anyone needs to be qualified, it is the candidate for any political post.

The only way to raise voter competency is through education and a cultural change geared towards celebrating civic duty on par with how we view voluntary military service.

I called for one on 2016 so.

Sounds like a trumpster move to me. Everyone has the right to vote.