I get nauseous every time I hear the name Ralph Nader. If all those votes cast for him for president in 2000 had gone to Al Gore, we might have been spared the Iraq war, the frat-boy alliance of George W and Tony Blair, and other horrors.

So I hate so-called third parties. I prefer to call them “fringe”. I don’t believe that voting has anything to do with the so-called likability of the candidates. Who cares which of them is the one you’d rather meet in the pub? Nor should voting be an act of protest. The Green party zealots who went for Nader because they said there wasn’t a dime of difference between Bush and Gore were tragically wrong.

Voting is a sacred duty of US citizenship and as such, the presidential contest is about one central question: in whose hands is the country most likely to prosper, be safe and come closest to the American promise of equal rights for all?

Because Trump and Clinton are such disliked and polarizing candidates, I understand why alternatives might appeal. Many voters do want to support someone who most purely mirrors their ideals. They don’t want to vote pragmatically or settle for the lesser of two evils.

This is a real dilemma. But 2016 isn’t the year for purity. Casting a vote for any of the alternative party or independent candidates in November could have truly disastrous effects.

With Trump on the ballot, the risk of unintentionally helping elect an unstable man who is clearly not prepared for the job is too big. After the past two weeks, it’s tempting to conclude that the pugnacious real estate tycoon has spontaneously combusted, like Old Krook in Dickens’ Bleak House. But by November, as has been true in most recent American elections, the gap between the two candidates will narrow. Even with all the self-inflicted wounds, Trump still starts out with a likely base of 170 electoral votes. Getting the next 100 needed for election will be extremely hard but not impossible. If Clinton is to win the swing states she needs to get to 270, she can’t have too many votes siphoned away by fringe candidates like the Green party’s Jill Stein or Libertarian Gary Johnson.

When I combed through their platforms and records, I, too, found a lot to like about Stein and Johnson, especially after I listened to their one hour, back to back interviews with Boston radio host Tom Ashbrook. Stein’s sincerity and smarts were evident. Since she twice ran for governor of Massachusetts and once before for president in 2012 (she received 469,000 votes, more than separated JFK and Nixon in 1960), she was more seasoned as a politician than I expected. Her calls for free college tuition and a 15% federal minimum wage mirrored those of Bernie Sanders, some of whose followers are using the Twitter hashtag #jillnothill. As would be expected of a Green candidate, her top issue is protecting “Mother Earth”, by dramatically reducing dependence on fossil fuels and banning nuclear power.

Her central message is a direct play for disaffected Democrats: “The [Democratic party] boat is sinking and it’s taking us down with it. This is the time to get off of that boat. We [progressives] have a lifeboat. It’s called the Green party, so let’s not sink together, let’s sail together!”

Johnson, the genial former Republican governor of a Democratic state, New Mexico, was popular in office, lowering state taxes, expanding jobs and attracting more businesses. Although he says he’s personally against abortion, he believes it’s the woman’s right to decide. His antipathy to stricter gun laws isn’t surprising for a libertarian, but will turn off liberal voters in urban areas. He’s for legalizing marijuana. His low-tax mantra will appeal to Republicans who think Trump’s economic plan is voodoo, to use an old Geroge HW Bush word. Johnson does seem a viable alternative to Trump for Republicans who just can’t stomach Clinton and perhaps for Sanders Democrats. Maine senator Susan Collins suggested recently that she’s considering voting Libertarian.

“I hope that people will see that we don’t have to sit by the sidelines and watch as the two major parties limit their choices to slightly different flavors of the status quo. It is, in fact, possible to join the fray, stand up for principles and offer a real alternative,” Johnson has said.

I’ve also watched some television appearances by Evan McMullin, a 40-year-old factotum of the Republican party, who is running as an independent candidate. Virtually unknown, he is hardly the GOP’s answer to finding a viable Trump alternative. I do give him credit for having the guts to try to drain Republicans away from Trump, but he just won’t be a factor in November.

None of this occasional likability translates into anything meaningful, however. None of these candidates could possibly win. So a casting a protest vote for any one of them is akin to throwing your vote away.

The most influence they would hope to wield is if any of them reach 15% in national polls. That way, they could be included in the presidential debates, gaining much wider national exposure. Johnson probably has the best chance to make it in, but Trump opposes anything but a direct one-on-one with Clinton. Some suspect this is a ruse to withdraw from the debates altogether, rather than get creamed by Clinton.

This extraordinary election is definitely a two-horse race. But the questions raised by the candidacies of both Sanders and Trump point to an uncertain future.

A politically savvy friend of mine, who works for one of the American TV television networks, told me he thinks Trump may be the last GOP presidential nominee. This friend, a Republican, believes the party will never recover from the Trump disaster. It will splinter into various other entities, some of them to sit it out on the fringe.

And what of those Democrats alienated by Hillary’s pivot away from the left as she moves into territory vacated by Trump, courting Republican establishment figures such as Henry Kissinger?

If there is no realignment, no recalibration, then the risk is that the angry voices on both left and right find no meaningful outlet. Third parties will never be a significant feature American politics, but after this election, the future shape of the two main ones is a question that cannot be neglected.