Gary Johnson, Donald Trump, and Jill Stein. | Official Campaign Photographs

We often use the term “two-party system” to describe our democracy, especially our way of electing members of the U.S. House of Representatives (and their counterparts in the state legislatures). However, we could use the more technically precise term “single member plurality voting system.” If you’re thinking of voting for a third party this November, you might want to keep that detail in mind.

We elect our presidents with a similar system. In the case of our presidents, the “single member” districts are each of the 50 states – we don’t have one national election for president, but rather 50 separate state elections. What happens in one state does not affect the outcome in any other state. “Plurality” means “most” (as opposed to a “majority,” which means “more than half”).

Everyone on Tuesday, November 8, will vote within his or her state. The candidate who wins the plurality, or most (but not necessarily the majority), of the popular vote in every state except Maine and Nebraska wins all of that state’s electoral votes, which is equal to the number of the two U.S. senators plus its representatives in the House. (OK, I know that the winner actually must win the vote of the Electoral College and not the popular vote, but in only four elections did the winner of the popular vote not win the presidency.) Add the electoral votes of each state won, and the winning candidate is the one who wins most of the electoral votes.

Yes, the majority of the electoral votes are required, but to win all of nearly each state’s electoral votes, a candidate essentially needs to win only a plurality of that state’s popular vote.

Third parties help the major party they most oppose

Because of our plurality system, third parties usually help their polar opposites. Extremely conservative third parties nearly always take votes away from the most conservative major party, the Republicans. This enables the Democrat in the race to win more easily. A party to the left of the Democrats typically takes votes away from the Democrat, thus enabling the Republican to win with relatively fewer votes.

This election, the Libertarian Party’s candidates are on all fifty ballots, and the Green Party’s nominees are on 44 states plus Washington, D.C. Former Republican but now Libertarian candidate Gary Johnson will probably take more votes from Trump, although his party’s social liberalism and anti-intervention positions might (but should not) confuse some progressives.

The Green Party certainly positions itself to the left of the Democratic Party, and I have had conversations with disgruntled Sanders supporters who are attracted to and support Jill Stein despite Sanders working for a Clinton victory. (Some voices argue that voting for either Johnson or Stein will help Trump.)

Neither third party will win many votes, but their candidacies can still affect the outcome of the races. And if they are relatively strong, they can help defeat the major party that is closest to them. The best example of this contradictory effect was in 2000 in Florida. George W. Bush defeated Al Gore by only 537 votes: 2,912,790 to 2,912,253. Yet Ralph Nader of the Green Party won 97,488 votes, nearly 200 times the size of Bush’s victory.

Was it a fact that Nader’s votes damaged Gore more than they did Bush? Some may wish that there was no such effect, but all polling studies found Nader drained “at least 2 to 5 times as many voters” from Gore as he did from Bush. The margin was so close that the state launched a recount, which was stopped by the Supreme Court as it heard Bush v. Gore. The decision by the Court let the original tally stand, so Bush won Florida, which gave him enough electoral votes to win the presidency. A similar outcome occurred in New Hampshire.

Was Nader unaware of the probable outcome? Not according to his nephew, Tarek Milleron, who bragged that Nader and his campaign wanted “to punish the Democrats, we want[ed] to hurt them, wound them.”

Progressives have a responsibility

All liberal and progressive individuals and organizations, especially left-of-center third parties, must take our system into account as they approach November 8. Either Secretary Clinton wins, or Donald Trump does. Some, such as the Green Party’s Stein, says that Clinton “is not different enough” from Trump to matter. “Neither party of the evils will do it for us,” she concludes.

I have to disagree with this argument.

With a Trump victory, unions, civil rights organizations, environmentalists, and other social movements will probably be thrown into defensive positions not seen since the years of President Reagan. With a Clinton victory, these movements continue operating in the same space and with promises from the Democratic platform that hopefully can be leveraged. I can’t guarantee success from a Clinton victory, but that is not a valid reason to not be fearful of the near-certain consequences of a Trump presidency.

More importantly, with a sound Clinton victory, the U.S. Senate hopefully goes back to a Democratic majority, so at least her Supreme Court and other important appointments and nominations will be heard and confirmed. If we can defeat a decent number of House representatives, perhaps the balance of forces changes enough to leverage the split in the Republican Party that is unfolding before our eyes. The larger Clinton’s margin of victory is, the more “political capital” she has going into her administration.

The mass social movements for progressive change are active in the Clinton candidacy. I suppose some could be blind to Clinton’s weaknesses, but by and large these movements are probably right on the money: a Trump victory will be extremely bad for the forces of progress. A Clinton victory, they know, gives us a fighting chance and will result in some favorable reforms – provided the GOP doesn’t completely obstruct her presidency.

When people who genuinely describe themselves as progressive interpret these mass movements as working for the wrong choice, they themselves are wrong and are missing the historic opportunity of working with these forces, of helping to move the center of gravity in a way that is real and quite important.

Worse the better?

Some people insist that a Trump victory will help progress because it will expose further the chaos of the system. This “worse is better (in the long run)” position also fails, because “worse” is actually “worse,” not “better.” When chaos erupts, the natural constituents of a front against the ultra-right do not automatically become activated. Chaos more often derails people, de-politicizes them, and sometimes moves them into ultra-right and conservative political positions.

The racist, misogynist and extremist sections of the Republican Party and the ultra-conservative movement are embedded into the Trump candidacy. Their influence has been very visible, and it will become exponentially worse if the party has the power of the presidency.

The left – if it exists to help the working class and poor, trade unions, African American equality, women’s equality, protection of the environment, LGBTQ justice, etc. – cannot complain that Clinton isn’t left-wing enough and ignore the certain damage to all of its constituents if Trump wins. If Trump wins, then the GOP has control of the presidency, the next three or four Supreme Court justices (which will immediately break the 4–4 standoff), and probably continued control of the U.S. Senate and House.

There are many genuinely good ideas at improving our democracy, many of which are trumpeted by the Green Party itself. But until the political temperature changes, neither of the two major parties will take on the issue of big electoral reforms. And the “two party” system will stand until both major parties face defeat by an insurgent party that stands to win the plurality.

Hopefully such changes are in the card for the future, but we’re not there right now. Secretary Clinton’s recent improvement in polling results is encouraging, but such signs should be taken with a grain of salt by progressive activists and democratically-minded voters until Wednesday, November 9.