If the candidates who were leading their races on the night of Nov. 4 had been declared the winners, Louisiana’s congressional delegation sworn in this week would look substantially different.

Mary Landrieu would have been starting her fourth term in the Senate, Edwin Edwards would have returned to the House for the first time since 1973 and Jamie Mayo would have been the second black member of the state’s delegation.

It also would have meant that our congressional delegates would be split evenly between Republicans and Democrats — one of each in the Senate, three of each in the House. Landrieu, Edwards and Mayo led their races with pluralities on Nov. 4. Louisiana, however, requires a majority to get elected.

In most states, it’s “first to the post”; the candidate with the most votes wins the election. In the past, that’s meant that just about the entire Congress is elected on the national Election Day. Only Louisiana in recent history has needed runoffs to complete its congressional slate.

While requiring a majority makes sense in theory, in practice it’s another story. Turnout in the Nov. 4 Senate race was 51.5 percent of eligible voters; in the Dec. 6 runoff it had dropped to 43.6 percent. So although Republican Bill Cassidy got the required majority in the runoff, he got a majority of a smaller electorate.

According to FairVote, a non-partisan organization working for electoral reform, “Decreased turnout dilutes the main benefit of a runoff: improving representation by allowing voters in primaries to select a candidate with broad popular support.”

I’m not trying to cast Cassidy’s election as illegitimate; he played according to the rules and won. It’s not the candidate’s fault if voters don’t turn out. It’s the citizens who didn’t show up that should be blamed and shamed.

Besides, if Louisiana had first-to-the-post elections, meaning the candidate with the most votes on Election Day wins, would Landrieu, Mayo and Edwards still have finished at the top?

The whole dynamic of the race changes under different rules. Candidates and their operatives would campaign and strategize accordingly. For example, would Republican Rob Maness have stayed in the Senate race if he knew his votes would hurt Cassidy enough to ensure Landrieu’s re-election with a plurality? Or would he have taken one for the conservative team and dropped out?

Would an election requiring only a plurality have drawn more moderate Republicans to the Senate race?

All of this is to say that the scenario I laid out in the opening paragraphs — victories for Mayo, Edwards and Landrieu — would not have been a sure thing if everyone knew from the start that a only a plurality was needed to win. So, if Landrieu’s fate was foreordained and she would have lost even under a first-to-the-post method, what’s the point of having a system that requires a majority?

Runoffs “can cost jurisdictions millions of dollars in extra administrative costs and nearly double the campaign funds necessary to win,” FairVote says.

“Negativity typically increases during runoff campaigns,” it adds.

That last statement is not news to Louisiana voters who had to endure another month of political advertising for the runoff.

But don’t expect a change soon. Democrats charge that Republicans know they do better in lower-turnout elections, which explains why GOP-controlled states have reduced early voting periods and enacted stricter ID requirements.

A recent piece on the conservative American Thinker website says Louisiana’s election system “ought to be embraced by conservatives everywhere” because it improves their election odds.

If that’s true, it’s unlikely we’ll see Louisiana’s Republican-led Legislature rushing to change the way we elect members of Congress.

Dennis Persica’s email address is dpersica@theadvocate.com.