The state senate passed a bill that approved Oregon joining the National Popular Vote Interstate Compact, a coalition attempting to bypass the traditional Electoral College system.
The legislation, which passed by 17 votes to 12, will now move for approval to the lower House of Representatives, which since 2007 has passed a number of similar bills.
Should it pass it will need to be signed into law by Democratic governor Kate Brown, who has signalled support for the bill.
The move will only come into effect however, once there are enough states committed to the compact to take their combined Electoral College votes total over 270; the threshold needed to win a presidential election. There are currently 189 committed votes.
"This is the fully constitutional way to ensure that every voter is politically relevant in every presidential election while preserving the Electoral College as the founders intended," John Koza, the interstate compact’s chairman, said in a statement.
Founded in the late 18th Century, each state has a number of electors in the electoral college proportionate to its population. It is made up of the sum of its number of senators (always two) and representatives in Congress.
Technically, on election day Americans cast votes for electors, rather than the candidates themselves, although in most cases the electors' names are not on the ballot.
The archaic system has come under increasing scrutiny since 2016, when Donald Trump lost the popular vote to Hillary Clinton by two percentage points, but won a majority of Electoral College votes. Another Republican, George W Bush, is the only other president in the last 130 years to win an election while losing the popular vote.
Republican state senator Alan Olsen criticised the move, complaining it could prove fatal to his party's future presidential candidates.
“If we get to the national popular vote, I don’t ever see a Republican president,” he said
Last week, New Mexico joined the interstate compact, which has also been adopted by California, Colorado, Connecticut, Delaware, Hawaii, Illinois, Maryland, Massachusetts, New Jersey, New York, Rhode Island, Vermont, Washington state, and the District of Columbia, the only non-state able to vote in presidential elections.
All have been Democratic leaning states in recent years.
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