THE UNITED STATES CONSTITUTION
We the People....
Article I
Section 4
3: Participation in the democratic process being both a right and a responsibility, it shall be compulsory for all eligible citizenry to attend a place of voting, have their name duly checked against an electoral roll, and submit a ballot paper in each Election for Senators, Representatives and the offices of President and Vice President
4: Failure of eligible citizens to participate in the electoral process shall be punishable by fines as determined appropriate by the Congress.
5: Each state shall have a constitutional responsibility to ensure that all eligible citizenry have the means and opportunity to exercise their democratic right and responsibility of participation in the electoral process for Senate, Representatives and the offices of President and Vice President.
In OTL most democratic societies emphasize voting as an
voluntary right in the same sense that free speech is a right
but everyone has the option of whether or not they wish to exercise it.
A small number of countries (including Australia) emphasize that it is NOT ONLY a right
but
ALSO a responsibility of citizens to participate in the process, in the same way that participation in jury service is considered a civic duty.
The main argument usually against compulsory voting is that "why should people be forced to vote for a party if they don't like any of them".
Well, in fact compulsory voting doesn't mean that at all.
Under the system in place in Australia, it is compulsory to turn up at the polling booth, get your name crossed off, receive a ballot paper and stick it in the ballot box.
It is NOT illegal to submit a blank ballot paper or even a paper with some obscene drawing scrawled across it.
What you choose to do (or not do) to your ballot paper is an entirely secret process.
The other argument that is sometimes raised against compulsory voting is that it somehow undermines the democratic process by making political parties "lazy" and taking their voter base for granted.
This argument I find very weak since, as already mentioned there is nothing to stop disillusioned voters handing in a blank paper.
Furthermore, anybody who knows how politics really operates will understand that under voluntary voting there are two unequivocal negatives.
a) Elections are often won NOT by the side with the best ideas, but with the side with the best "get out the vote" machine i.e. the most money.
b) Extremists are more motivated to vote as a political block than Joe Average therefore political parties find that their agendas become hi-jacked by these motivated minorities (hello Republican Party?

).
So in my ATL lets imagine that Thomas Jefferson and the Founding Fathers in their infinite foresight and wisdom decided
that instituting compulsory voting was an important pillar of ensuring the continued legitimacy of the Republic and it's healthy democratic process.
What influence might this have had on politics?
Note that I have carefully worded the new insert to the constitution as "eligible citizen", meaning NOT universal suffrage.
I am assuming that universal suffrage would continue along much the same path as OTL.
One probable result would be to make both sides of politics more centrist which means less leverage to the Religious Right in American politics.
Would prohibition still have been introduced?
Would Wade vs Roe be as incendiary as it is today?
Thoughts?