No, I'm saying I want to change the way people vote for Congress.
Ok, then you are not talking about how we elect a president? If you are only talking about electing members of Congress, there are no restrictions on how many parties can put candidates on a ballot so what would you change?
At present it's First Past the Post.
In Germany they have a duel system. The people vote twice. First for FPTP representative for their area, the second for Proportional Representation.
This means that the FPTP winners get their seats. Then the rest are allocated based on PR.
So, take the 2009 German election.
The CDU/CSU gained 218 seats through FPTP. The SPD gained 64 seats, die Linke gained 16, Alliance '90/die Gruene gained 1.
Then with PR the CDU/CSU gained 239 seats. Which means they got 21 seats allocated to them via PR.
The SPD got 146 seats via PR, which means 82 were allocated to them via PR. The FPD which gained no seats via FPTP but gained 14.6% of the PR votes then were given 93 seats.
The NPD, the far right party gained no seats with FPTP and did not gain 5% of the votes so they got zero seats. All in all there were five parties in the Bundestag.
So the CDU/CSU gained 33.8% of the votes and 38.42% of the seats (because of course people vote for parties that don't get either a FPTP or a 5% threshold so the parties that do gain seats will get a higher percentage than they got for votes.
The CDU/CSU and FPD managed to gain 53% of the votes and so formed a coalition.