When Americans go to the ballot box during a presidential election they do not cast their vote directly for a presidential candidate. Instead, they choose a group of electors – 538 in total – who in turn have the power to elect the president.

Each American state has slightly different rules on how the electors are selected.

In general, state political parties control the selection process by choosing, before the election, a group of people they trust and who have agreed and/or pledged to vote for their party’s nominee.

In most states, all preselected electors of the political party that receives the majority of the state’s popular vote become the presidential electors for their state. According to the Constitution, members of the US Congress, as well as any person “holding an office of trust or profit under the United States”, are not allowed to become presidential electors.

Consequently, the electors are an eclectic group of people. Some of them are well-known state politicians, including current and past members of state legislatures and governors. Others are just unknown private citizens with loose ties to a political party, including at least one teenager involved in politics for the first time.

While there is no federal law or constitutional mandate that presidential electors actually vote for the candidate they have originally agreed or pledged to vote for, 29 states have state laws and regulations that try to restrict their freedom.

The law in each state is, once again, slightly different. But most states with restrictive regulations simply state that electors are “required” to vote for the nominee of the party that selected them.

Electors who go against this “requirement” can face a fine (for example, US$1,000 in Washington), felony charges (in New Mexico), or simply end up immediately replaced by a different elector (Minnesota, Montana, Nebraska, Nevada, North Carolina, Oklahoma and Utah).

In 1952, the US Supreme Court argued that states and state parties are allowed to require a pledge from their potential electors. The decision said such a requirement was not unconstitutional, even though it was legally unenforceable because it would violate the electors’ assumed constitutional freedom.

Therefore, some believe the Supreme Court would not uphold any state penalty against electors changing their vote.

If every elector votes as they are supposed to, Trump will be elected president with 306 Electoral College votes, while Hillary Clinton will receive 232 votes. But this is unlikely to happen.

An online petition, which has collected nearly 5 million signatures, is calling on Trump electors to vote for Clinton instead. If only 38 out of the 306 Trump electors decided to do so, Clinton would be elected president.

This, however, is not going to happen. It is extremely improbable that any Republican elector would ever agree to flip and vote to elect the Democratic candidate. But this is not the only option.

A group of Democratic electors who call themselves the Hamilton electors have been trying to convince other Democratic electors to break rank and vote for a Republican president that is not Trump. Their choice would probably be Mitt Romney or John Kasich, but they are open to any suggestion from the Republican camp.

Their hope is to attract enough electors from both sides to gather 270 Electoral College votes and elect a Republican who is not Trump.

This option seems to be gaining some momentum. A Democratic elector from California has filed a lawsuit seeking that Clinton release her electors from their pledge. And a Republican elector from Texas has announced he will not vote for Trump.

What could happen is that 37 out of Trump’s 306 electors decide to either join the Hamilton electors or simply vote for a different Republican candidate.

If at least 37 Trump electors do not vote for Trump on December 19, then no candidate will have the absolute majority of Electoral College votes required to be elected president, and the US House of Representatives will choose the president among the three candidates with most Electoral College votes.

Although even this scenario is a long shot, it is the most likely to happen – if anything at all is going to happen on December 19. It is also, politically, probably the most desirable outcome.

If given a choice, Republican members of the House may be able to reach a compromise with their Democratic colleagues and elect “the other Republican”. This would prevent Trump becoming president, and avoid having an obscure institution such as the Electoral College simply change the election outcome with a move many would perceive as anti-democratic.

Alternatively, should the House decide to elect Trump anyway, they would be assuming all the responsibility of their choice – and their constituents should take note of their action.

What will happen is probably a record number of electors breaking their pledge and voting for a different candidate. Whether this will be of any consequence depends on how many Trump electors are persuaded to change their vote.

The bottom line is that even though many Americans have once again started to mock the Electoral College as an undemocratic institution, it does play an important role in the US constitutional design.

As Alexander Hamilton pointed out in his Federalist #68, the Electoral College:

… affords a moral certainty that the office of president will seldom fall to the lot of any man who is not in an eminent degree endowed with the requisite qualifications.

Every little detail, from having the electors vote about a month after the election to the requirement that they never meet as a whole (but only in their own state capitals), suggests the electors are being asked to ponder, consider, and make a conscious decision.

The Electoral College has survived 227 years and, arguably, has never truly been needed. Now would be a good time to use it.

This article was also published on The Conversation 

DISCLAIMER: These opinions are those of the author, not of Flinders University or other affiliated institutions.

Dr Rodrigo Praino is a lecturer in Politics and Public Policy at Flinders University’s School of Social and Policy Studies and director of the Graduate Program in Public Administration online. He is an expert in American politics and elections and has published extensively in the field. His work has appeared in journals such as American Politics Research, Social Science Quarterly and Congress and the Presidency. His academic work has featured prominently in the international media, including the Washington Post, Politico, the Huffington Post, the Pew Research Centre and the Discovery Channel.