Well, in my opinion, you hold an election and the results speak for themselves. The only valid reason to challenge an election is if you can prove fraud occurred in the voting process.
In the case of the presidential election in 2004, when the DEMOCRATS repeatedly tried to claim they could somehow psychically discern what was in the mind of a voter who chose not to vote for their candidate, it was a travesty. And they lost. Both in the election and in the courts.
We really need to get the courts out of our elections. Suing because you lose is just sad.
Coincidentally, did you know that the first election win by Obama came about because he sued to have every one of his opponents removed from the ballot? Wow, that's ethical.