(CNN) - California will allow voters to change their party affiliations as late as Election Day, a move that could have major implications for the large cache of delegates up for grabs in the state's upcoming Democratic primary.
Democratic Gov. Gavin Newsom signed legislation on Thursday, effective immediately, doing away with the previous cutoff of two weeks before Election Day.
The move could open up a myriad of possibilities for rival strategists to make a ploy for the biggest single delegate prize, as they already have in other states. Some conservatives in South Carolina are trying to interfere in the Democratic primary by encouraging Republicans to vote for who they believe is the weakest candidate to take on President Donald Trump in November.
Instead of having to reregister to vote to change their party affiliations, Californians will now simply submit signed requests to switch parties to state election officials. Their registrations will then be immediately changed and they will receive the appropriate ballots, according to the bill.
Trump appeared to encourage the tactic of rival party interference during a rally in New Hampshire the night before the state's primaries.
"So I hear a lot of Republicans tomorrow will vote for the weakest candidate possible of the Democrats," Trump said Monday. "Does that make sense? You people wouldn't do that. My only problem is I'm trying to figure out who is their weakest candidate; I think they're all weak."
He later added, "If you want to vote for a weak candidate tomorrow, go ahead, pick one. Pick the weakest one you think, I don't know who it is."
Similar efforts have taken hold in South Carolina, which has an open primary that allows eligible voters to cast ballots in either party's primary. Two Republican operatives told CNN that they looked to disrupt Democrats' process of selecting a nominee, with supporters of the strategy urging participants to skew support for Democratic candidates -- namely democratic socialist Bernie Sanders -- in hopes of sowing an future ideological contrast with Trump.
The strategy is a serious obstacle for Joe Biden, who lagged significantly in Iowa's and New Hampshire's recent tallies and whose future in the race could depend on a boost from the Palmetto State. The South Carolina Republican Party has said it is not endorsing the strategy, and it remains unclear how many Republicans will participate and to what effect.