An update: On Tuesday evening, Nebraska Republicans fell one vote short of changing Nebraska's system of electoral votes. The original post follows: 

Politically speaking, Nebraska has always done things a little differently.

The state has the only unicameral legislature in the nation. In May, it became the first Republican state in 40 years to ban the death penalty (although voters will get the final say in November). And Nebraska is one of only two states to split its electoral college by congressional district.

That last quirk might change very soon. A bill looks set to pass the state legislature as soon as Tuesday that would make Nebraska a winner-takes-all state by the next presidential election. Its passage is not a given, but there's a good possibility.

That would mean that never again -- or at least not in the foreseeable future -- could a Democrat hope to take an electoral vote out of Nebraska as Barack Obama did in 2008 when he won the Omaha-based 2nd Congressional District.

Here's a history of Nebraska's unique system -- and a more detailed look at what the proposed changes might mean.

How it works

Since the 1830s, a winner-takes-all electoral vote system has been the standard in the country. Today, 48 states and the District of Columbia award all of their electoral college votes to the winner of the state. But Nebraska and Maine have set up a system that makes it possible for both the Democrat and the Republican to get a vote.

In Nebraska, only two of its five electoral votes go to the state's overall winner. The three others go to the winner of the state's three congressional districts. The process mirrors some states' winner-takes-most strategy in the primaries.

Why Nebraska does it that way

Nebraska's state lawmakers decided to move to its current system in 1991. Supporters said it would make Nebraska more relevant on the national stage because suddenly at least one or two of its electoral votes would be in play. Presidential candidates would actually come to Nebraska to campaign, they said. They based their model on Maine's, which has been used in that state since 1972.

The planned competitiveness of Nebraska never really panned out. All five of Nebraska's electoral votes went for the Republican presidential candidate from 1992 until 2008. That year, Obama's campaign set up a ground game in Omaha, dispatching hundreds of field workers to the district and eventually winning it by just more than 3,000 votes.

Here's Obama reminiscing about that year in a speech in Omaha in January:

In a January 13, 2016 speech in Omaha, NE, President Obama reflected on his 2008 run, and winning one electoral vote in the Cornhusker State. (The White House)

Why Republicans want to change it back

One of the bill's most vocal proponents, state Sen.Beau McCoy, says Nebraska should speak with a unified voice, especially since a split electoral system doesn't make much sense if Nebraska is one of the only states to do it. "To me, it’s a matter of fairness," McCoy told the Omaha World-Herald. "It’s not partisan politics."

Political observers such as the University of Nebraska's Kevin Smith think there's also a clear correlation between Obama winning an electoral vote in the state in 2008 and the Republican-led effort to stop letting congressional districts have a say in the state's electoral vote allocation. Why keep a system that benefits Democrats even a little bit when Republicans have the power to change it back?

"I think if Obama had failed to take that electoral vote and all the electoral college delegates from Nebraska went to the Republican, I don't think they'd be having this debate right now," Smith said.

But reverting to a winner-takes-all system has eluded Nebraska Republicans, who for all intents and purposes control the nonpartisan state legislature and all levers of the state government. This will be at least the 15th time Republicans have tried to change it back to a winner-takes-all system. Last year, they got close, falling just two votes shy of breaking a filibuster.

Why Democrats want to keep it

Relevance!

"This is absolutely not the year to make ourselves irrelevant," Sen. Sue Crawford told the Omaha-World Herald.

Plus, Democratic presidential front-runner Hillary Clinton has indicated that she'd like to follow Obama's playbook in Omaha. She held a rally in December there, where billionaire and Clinton supporter Warren Buffett had this to say: "This district will be in play in 2016, and one [electoral] vote could be important."

That won't be true any longer if Republicans get their way this week.