In the United States there are two major parties, both of which consist of big tent coalitions. The Democrats start from the socialist left and run to moderates who could just as easily be moderate Republicans. Republicans do the same from the right, from the Neo-Nazi alt-right to people who could just as easily be moderate Democrats.

Both parties have the same problem. If the various constituencies that make up the party fail to compromise and unite, the other side wins.

The Canadian left typically suffers from the same problem, despite having three significant parties. The Conservative Party in Canada typically pulls 35 to 40 percent of the vote, but managed to rule for a decade because of divisions on the left (and moderate/centre-left). For a decade, “progressive” or socialist democrats supported the New Democratic Party while moderate and left-centre Canadians supported the Liberals. This created an environment where the Conservatives could win without a majority.

In the US there is no significant 3rd party, but people can still make a protest vote for a minor party or a write in. They can also simply stay home on election day. In 2008, moderate and progressive Democrats both turned out in large numbers, handing victory to the Democrats and Barak Obama. Progressives came out again in sufficient numbers to at least put Obama back in the White House, even if it didn’t lift congressional Democrats. However in 2010 and 2014 many progressives stayed home and some moderates switched sides resulting in Republican gains in congress and at the state level.

As successful as Republicans have been in recent years, they have been held back to an extent by infighting in their own ranks. However, the cracks really started to show in the 2016 race when “establishment” pick Jeb Bush suffered humiliating defeats and anti-establishment candidates like Ted Cruz and Donald Trump soared. Ultimately the GOP was able to silence the “Stop Trump” forces within the party and pull together, especially after the election. However, the divisions haven’t gone away and the cracks were clearly visible when the Republican Health Care plan went down in flames.

According to the Associated Press, following the flame out of the health care plan, Speaker of the House Paul Ryan said: “We were a 10-year opposition party where being against things was easy to do. You just had to be against it. And now, in three months’ time, we try to go to governing where we actually have to get … people to agree with each other.”

And that’s the rub. It’s easy to hold together and build on a coalition in opposition, it’s far more difficult when you’re actually in power and the various factions want their conflicting demands met.

In Canada, Liberals and the NDP (and leftish Canadian independents) tend to become almost a united front when Conservatives are in power. When there’s an election or the Liberals are in power, all that cooperation and general good will vanishes faster than a revenue surplus.

In the US, the left didn’t really think the Republicans would be a threat and they shouldn’t have been. Outgoing President Barack Obama was immensely popular and every poll showed he could have easily claimed a third term. The economy was booming, unemployment was very low, more Americans than ever had health insurance and wages were rising for the first time in decades.

A win seemed like such a sure thing that the left-centre and progressives sabotaged themselves by running the election as if it was ultimately between the two sides of the party and not Democrats vs. Republicans. It was the same thing that Republicans did last week. None of them liked Obamacare. After voted to defeat it multiple times during the Obama years they thought its destruction was a given but the battle over what to replace it with became so intense that Obamacare survived and is now more entrenched than ever.

There is a lesson for non-conservatives of every stripe in the health care fiasco. Bernie Sanders supporters are fond of pointing out that the Democrats can’t win without them, and that could be true at the moment. They should also be aware though that they can’t win without the rest of the party. If they actually pursue the “#DemExit” strategy their best case scenario is mimicking Canadian politics.

However, despite the American lefts romanticization of Canadian politics, that wouldn’t serve them well: The “progressive” / democratic socialist NDP does have seats in parliament but has never actually been in power, nor do they look like they will be anytime soon. If they have an idea or platform that becomes popular enough to win significant votes, the Liberal party adopts it and leaves them on the fringe holding on to their less popular ideas.

There is also a possibility that if the progressive wing actually walks away that the Democrats can win without them, the same way the Liberals have in Canada. Democrats would be free to reach out to moderate and fiscally conservative, socially liberal independents and Republicans. Democrats would be able to say ‘No, we’re not socialists, the socialists are over there and we’re not the racist, sexist, alt-right – those people are over there. We’re the party for everyone else’.

On the left and the right, when big tent parties work together, compromise and are willing to accept partial victories, they win. When they fail to do all that they lose. When hard-core ideologues refuse to budge and issue ultimatums and lists of demands they inevitably wind up losing considerable ground on their core issues instead of making modest gains.