Washington Gov. Jay Inslee’s decision to drop out of the race for the Democratic presidential nomination won’t directly affect the outcome. But it does point to the difficulty that lesser-known candidates will have breaking away from the pack when they offer the same bucket of issue stances and priorities as the leading, better-known figures.

Inslee based his entire presidential campaign on his dedication to combating climate change. One might have thought that would be a winning strategy. After all, polls show that fighting climate change is a top priority among Democratic voters and one of the top two priorities among very liberal voters. But that ignores the dynamics of a multi-candidate race.

Any race as tussled as the Democrats’ has a tiered system of candidates. Those in the top tier in the early stages are normally those who start the race with a national presence and high name identification. Thus, early polls in Democratic races in 2008 and 2016 showed Hillary Clinton had early leads. On the Republican side, polls ahead of the 2008 election showed former New York mayor Rudolph W. Giuliani with the national lead until well into 2007, and early polls for the 2016 primary showed former Florida governor Jeb Bush in front of the pack.

These candidates know their voters’ preferences inside and out. They tend to offer platforms that touch upon all factions’ preferences, with tilts toward those they are most aligned with. As a result, lesser-known candidates trying to gain attention have most of the field preempted. If all they offer is something a better-known candidate is already selling, they don’t have a comparative advantage and therefore don’t rise.

That was Inslee’s problem in a nutshell. His problem was not, as elections analyst Nate Silver has said, that Democratic voters aren’t really voting on issues. His problem is that every leading Democratic challenger agrees with Inslee and has his or her own, credible plan to confront climate change. Even “moderate” Joe Biden issued an early and detailed plan to tackle climate change.

Lesser-known candidates who do break out almost always identify one or two issues that aren’t being touted or emphasized by the front-runners. Former Vermont governor Howard Dean rose dramatically in the 2004 race by pushing his opposition to the Iraq War at a time when almost every other Democratic candidate had either voted for it in the Senate or House or still backed it. That fact was clearly not lost on a then-obscure Illinois state senator named Barack Obama, who was waging his own insurgency in the Democratic Senate primary that year. His early opposition to the war clearly helped him win an upset victory in that primary and was used with devastating effect against Clinton in 2008.

Successful Republican insurgents have employed the same tactic. 1996 candidates Pat Buchanan and Steve Forbes shocked the political establishment by using the culture war (Buchanan) and proposals for a flat income tax (Forbes) to gain an edge on the apparent conservative favorite, then-Sen. Phil Gramm of Texas. In 2000, John McCain used his support for bipartisan campaign-finance reform and climate change legislation to mobilize party moderates and become George W. Bush’s surprise final challenger. In 2008, Mike Huckabee eclipsed Mitt Romney and former senator Fred Thompson of Tennessee, each of whom was better known and financed, by seizing upon evangelical Christians’ desire for one of their own to be the party’s nominee.

Even Donald Trump employed this time-tested tactic in 2016. He was the only candidate to embrace trade restrictions at a time when party orthodoxy was staunchly free trade. He also rejected cuts to Social Security and Medicare, something his rivals were loath to do because of the intellectual sway that then-House Speaker Paul Ryan’s budget plans held over the party elite. Even Trump’s much-hated proposal to ban Muslim immigrants captured a voter sentiment the establishment had missed. Each of these issue stances allowed him to stand out from the pack and consolidate his celebrity into something that, to GOP primary voters at least, passed for a credible and desirable platform.

Most of the rest of the Democratic field now faces the same conundrum that sunk Inslee. There’s no viable running room to the left of Sens. Bernie Sanders (I-Vt.) or Elizabeth Warren (D-Mass.), and Biden is sucking the oxygen out of the more moderate wing of the party. Most of the other Democratic hopefuls remain mired with 2 percent of the national vote or less and will soon have to decide whether to follow in Inslee’s footsteps.

Inslee’s decision highlights how hard it is to get traction in a national presidential race. Expect to see a dramatically narrowed field by the time the holiday season starts.

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