When the New York Times reported that former New York City Mayor Michael Bloomberg is drawing up plans for a potential independent candidacy for president, speculation about how his entry might scramble the 2016 race seized the spotlight. Yet this was déjà vu all over again — at almost exactly the same point in the presidential primary process eight years ago — on December 31, 2007 – the Times broke a very similar story about the then-Mayor’s equally intriguing dalliance with an independent candidacy.

Back then, Bloomberg was said to be motivated by the opening in the political center supposedly provided if the major candidates were Barack Obama and Mike Huckabee; this time he apparently sees daylight in a possible Bernie Sanders-Donald Trump match-up.

As someone who has reported and researched independent political movements for years, count me among those who continue to doubt that Bloomberg will actually run — once he looks hard (again) at the actual obstacles to victory.

Third-party challenges used to be a lot more viable in American politics. The Republican Party was originally a “third party,” and its candidate Abraham Lincoln benefited from a four-way race for the presidency in 1860. Lincoln won both because the slavery issue was undermining all the incumbent parties, and because back then it was far easier for new parties to nominate their own slate of candidates and get them on the ballot.

All the members of a new party needed do was to convene, nominate candidates, and then print and distribute their ballots to potential voters. That method allowed new parties to arise quickly. They could avoid the “spoiler” problem by cross-endorsing candidates of existing parties when that was strategically useful, or running their own contenders whenever they wanted to.

The cross-endorsement option, which is called “fusion voting,” was later outlawed by Democratic- or Republican-controlled legislatures in most states, part of a wave of changes that centralized control of the ballot in the hands of the state and began the entrenchment of our two seemingly permanent major parties. Actually, fusion never went away in New York (which regularly has five to six functioning parties represented on the ballot and sees about 20 percent of the statewide vote go to lines other than the Democrats or Republicans) and is experiencing a bit of a revival as the Working Families Party, its chief current proponent, expands nationally with a base in labor.

In recent decades, a handful of independent or third-party candidates have managed to win office at the state level. Think of Connecticut’s Lowell Weicker or Minnesota’s Jesse Ventura, who won governorships; or Maine’s Angus King or Vermont’s Bernie Sanders, elected independent US Senators from their states. Those victories occurred under conditions that were far less hospitable than those that lifted Lincoln, but it isn’t hard to tease out what worked: In each case, the independents had easy access to the ballot; substantial media coverage (including participation in televised debates with the other major candidates), and sufficient funding to be competitive.

Today, a potential third-party presidential candidate faces a much steeper climb. Some states have arbitrarily high signature requirements merely to get on the ballot, a privilege that they automatically confer on Democrats and Republicans. Worse, there’s no guarantee that third-party candidates will be included in the presidential debates, since the Commission on Presidential Debates (which is run by Democratic and Republican party apparatchiks) has set an arbitrarily high bar of 15 percent in national polling before it will include additional candidates–and one or both of the major candidates might drop out of those debates were a third candidates to be included.

Money is also a huge obstacle, though the possibility of someone getting tens or hundreds of millions of dollars in small donations no longer seems that far-fetched in the age of the Internet and Kickstarter.

None of this is to say that a third-party candidate can’t have an impact even in losing. Ross Perot effectively shifted the national debate to his pet issue–deficit spending–with his maverick campaign in 1992. In the past, third parties have succeeded by getting their concerns and ideas co-opted by one or both of the major parties. It was third parties that first introduced such reforms as the direct election of Senators, unemployment insurance, and women’s suffrage, for example.

But if we wanted to make it easier for third-party candidates to compete effectively in the race for the White House, we’d insist on much easier access to the ballot for candidates who can demonstrate a baseline of broad support; a lower barrier to entry to the debates (say, 50% of the public saying they want to hear from candidate X, rather than a popularity ranking); and a revival of public matching funds, for starters.

The Electoral College remains a much bigger obstacle, of course, and today it must be said that the likeliest effect of a muscular third-party bid by someone like Bloomberg would be to prevent any candidate from gaining an electoral vote majority, throwing the contest into the House of Representatives, where each state delegation would have one vote. From the point of view of representative democracy, that is a nightmare scenario. It would be far better if we first adopted the “National Popular Vote” solution, where every state would give its electoral votes to the candidate getting the most overall votes nationwide. (Eleven jurisdictions controlling a combined 165 electoral votes have already agreed to do so, once states comprising at least 270 votes join the compact.)

Still, there’s a reason why a Donald Trump versus Bernie Sanders election looks so tempting for an avowed centrist like Bloomberg. Neither Trump nor Sanders are from the mainstream of their respective parties. Trump has previously voted Democratic and dallied with running as candidate of Ross Perot’s Reform Party back in 1999-2000. Sanders is still not a registered Democrat in his home-state of Vermont, where has long defined himself as a socialist and an independent. Trump and Sanders actually best represent the shadow wings of each of the major parties–the outsider caucuses where people with less money and no great love for their party’s establishment have clustered.

Until we change the underlying rules of the electoral game, making it more open to challengers and ending the perversely undemocratic impact of the Electoral College, the odds of a short, Jewish, divorced, autocratic , pro-choice, anti-gun 73 year-old billionaire seem roughly as long as the New York Jets winning the Super Bowl.

Micah L. Sifry, the co-founder of Civic Hall, is the author of numerous books, including Spoiling for a Fight: Third-Party Politics in America.