On Sunday, the Libertarian Party nominated former New Mexico Governor Gary Johnson to lead its 12th charge for the US presidency since 1971. With Republican and Democratic voters having mathematically nominated Donald Trump (right in photo) and Hillary Clinton (left) - candidates broadly unfavorable to the US electorate - Libertarians believe that 2016 could finally be their year. Laissez-faire capitalists who favor decriminalization of drugs and a noninterventionist foreign policy, the Libertarians could pick off Republicans and Democrats who feel that America's two-party monopoly crowds out ideological diversity.

"I will be the only third-party candidate on the ballot in all 50 states," Johnson said when he accepted his second-ballot nomination. "I'm it."

"I am fiscally conservative in spades and I am socially liberal in spades," Johnson said

The White House has changed hands between the two establishment factions since the founding of the Republican Party in 1854. Of the 535 legislators in the bicameral US Congress, only two are independents - and one of those, Vermont Senator Bernie Sanders, is running for the presidency as a Democrat. On the other side, Trump was hardly a Republican before he wrapped up the party's 2016 nomination: He won two primaries for the Reform Party in 2000 and had been a registered Democrat and major donor before that. The remarkable 2016 runs of Sanders and Trump would not have been possible had either tried to work outside of the system, but that's just how the system is rigged.

Americans who are, say, passionate about environmental protections often find themselves voting for Democratic incrementalists in order to stave off what they fear would be a full-on Republican assault on the ecosystem. On the right, voters whose single issue is a flat tax throw their lot in with anti-transgender Republicans who call for an end to reproductive choice and mandatory prison sentences for nonviolent criminals.

Much of this has to do with the Electoral College, a complicated state-by-state proportioning of the presidential vote that makes the national election a local affair and discourages protest votes in tight competitions. In 2000, for example, the Green candidate and consumer advocate Ralph Nader enjoyed modest nationwide support from left-wing Americans. However, voters who might have been sympathetic with his calls for universal health care and better environmental stewardship were discouraged from supporting him in states where the two-party race was tight, lest they ruin the chances of the Democratic nominee, Vice President Al Gore. Through no fault of Nader's own, Gore lost that year, but the Green candidate has been blamed for ushering in the presidency of political scion George W. Bush, whose eight-year reign has discouraged many progressive voters from looking outside the Democratic Party ever since.

"America's winner-take-all electoral system and the Electoral College makes it very hard for new parties to enter the political arena," Torben Lütjen of the Göttinger Institute for Democracy Research wrote in an email. "There are surely a lot of Sanders supporters out there who would love to vote for him instead of Hillary Clinton in a general election. But, since supporting a third party candidate could mean wasting your vote and essentially helping elect a Republican to the White House, they will surely think twice."

Sanders has inspired many Democrats to look for alternatives to their party's likely candidate

The two-tone spectrum

The most successful modern third-party candidate was Texas billionaire Ross Perot, who sought a protectionist trade policy and in 1992 filched voters equally from the Republican incumbent, George HW Bush, and the Democratic challenger and eventual winner, Bill Clinton. Perot finished with 19 percent of the popular vote, becoming the most successful non-mainstream candidate since Teddy Roosevelt sought revenge on the Republicans by launching the Progressive Party in 1912, failing to win the presidency, but succeeding at costing his former faction the election. Perot ran again in 1996, seeking to unseat Clinton by forming his Reform Party, but this time around Republicans and Democrats were smarter, keeping him off the stage at the debates. The Reform Party peaked two years later, sending the professional wrestler, actor and conspiracy theorist Jesse "The Body" Ventura to govern Minnesota, though he quit the party a year into his term.

Perot (center) frequently asked his opponents to "let me finish"; he wasn't allowed back to debate in 1996

US states are often described as "red" or "blue," meaning they lean, respectively, Republican or Democrat. States too close to predict are "purple," their redness or blueness determined on election day. But there's the Green Party and the red-left Workers World Party, Socialist Workers Party and Socialist Equality Party. The right has free-market Libertarians, the protectionist Reform Party and the God-fearing American Independent Party. Surely such inspired ideologies deserve their own shades in the American political rainbow. But part of the problem is that the two major parties have become brands of their own - privately financed cults of personality in which ideologies are shaped to fit those of the biggest donors but also to appeal to the perceived needs of voters, who are treated in many cases as consumers.

"Politics in the USA are not - as is common in parliamentary government systems - formulated and steered by the parties, but negotiated through issues networks, in which like-minded political advisers, campaign managers, lobbyists, politicians, administrative elites and journalists work together to try to push through their ideas and interests," Josef Braml, the editor-in-chief of the German Council on Foreign Relations Yearbook, wrote in an email. "Parties in the USA have little means of sanctioning their representatives and senators or disciplining them to push through political agendas," he added. "In contrast to Germany, US parties have no authoritative power in the legislative process. With exception to their electoral function, parties have a diminished role in the USA."

This gives individual politicians outsized sway on many issues their constituents support, but which their party does not. By contrast, in Germany, for example, politicians pretty much have to toe the party line, if they want to have any influence at all.

Americans may have little choice when it comes to political parties, but it is much easier to vote out a politician you don't like. In Germany, politicians can remain in office for decades solely by being on a so-called party list, regardless of whether or not he or she has garnered enough votes at election time. A high position on the list guarantees a seat in parliament, even if you lose your district to another candidate. This system essentially rewards party loyalty over defending the interests of your constituents who elected you.

And still, voters in the US tend to remain strategically loyal to parties with which they have little in common, prefering to play defense rather than break ranks for candidates who profess beliefs more in line with their own. That alone is good grounds for expanding the US system to allow for multiple parties with nuanced platforms rather than trying to jam dozens of competing ideologies into two chaotically big tents.

"In Germany, votes are easier represented in the parliament, and we mostly have coalition governments," the democracy researcher Lütjen wrote. "That makes it more rational to support a smaller party - one, that still might be able to enter a coalition with a bigger party. Your vote is not lost."

A system like that might appeal to Americans, as well, and theoretically it's up to the voters themselves to decide. So far, however, they appear to have voted against it.