What would stop Republicans from voting in our primaries?

The number of people who would take time out of their lives to vote for someone they don't support in a primary is minuscule. This should not be a concern going into 2020.

Here in California, there will also be propositions, and local stuff, so (if I were a Republican) why wouldn't I also take the opportunity to toss a little chaos into the Democratic convention?

Against Mitch in the primary?
they can still vote dem in the general.

It would be the easiest and cheapest way to get rid of him


Is it the Dem Party worrying more about getting matching money for voters then getting rid of a so obviously compromised Representative.

Remember “Operation Chaos” some years ago? Was a campaign by the Repugs to get them to change their registration to Dem and vote for the worst candidate in the primary. They WILL pull this kind of crap in an open primary.

Every state should have closed primaries. Furthermore, in closed primary states, if you don't pick a party, don't whine about not being to vote in the primary. It's kinda like not picking a softball team to join, then complaining when you don't get to play softball. You can't play if you don't join.

so shitting on them in the primary is like not a good way to pull them in.

that if you are not a member of a party, you do not get to pick who represents that party "s**ting" on them?

How many clubs allow people who are not members of that club to pick who are the leaders of that club? How often do you see the members of Club A allow members of rival club B to come and vote for who will lead club A? If they want to vote for the leaders of club A, it is the easiest thing in the world to become a member of club A.

All other parties are effectively locked out because of our electoral systems.

So portraying the Democratic or Republican parties as just private clubs, or worse 'sports teams' is either naive or dishonest. They are, in reality, public institutions with a privileged role in the political process.

If you are an Independent or non-aligned voter, you simply change your voter registration to Democratic if you want to vote for a Democrat in a Primary, or to Republican if you want to vote for Republican in a primary. There is absolutely no restriction on doing this, other than the need to do it a certain number of days before the primary. Whether or not the Democratic Party and the Republican Party are de-facto institutionalized political parties, sports teams, or clubs does not change this. If you want to vote in a closed primary, you simply change to the party that you want to be in within the allotted time before the primary. One can always change back to Independent or non-aligned afterward if one chooses. Why do you think this is "s***ting" on people?

one would think if it was so effective they would keep doing it. In fact, they would expand it as they do with all the other dirty tricks they have tried and which worked.

Personally I don't think it worked. And closed primaries just drives new voters away.
But if you do think this tactic works, trump is facing three primary challengers.

You can set limits, blocking changes for some time before the actual primary, but that is pretty much all you can do.

That of course plus the fact that despite 'operation chaos' there is basically no evidence that Limbaugh's efforts or any other organized party raiding efforts had any significant impact on election outcomes.

The capability of Repugs to do dirty and underhanded things and get away with it

It is much ado about nothing. Its our version of voter fraud. We should at least try to be rational evidence based humans.

if you are a registered republican you cannot vote in the democratic primary!!

in advance

Other than that, there's nothing to stop them from changing parties.

The surest way to be rid of Trump is to deny him the nomination.

The problem will still not address those states that allow one to change one's voter registration to D in order to vote in the D primary sometimes as little as a day or two before the primary election and change it back the next day, but it is a deterrent nonetheless.

I really don't get why all state's primaries should not be closed. I likewise don't understand why it should be acceptable for states to deny a Republican primary when there are Trump challengers with the wherewithall to qualify.

In California, only registered Republicans can vote in the 2020 Republican presidential primary. However, the Democratic party (and the Libertarian, and the American Independent, parties) will let voters registered as No Party Preference vote in their 2020 presidential primaries*. For all other offices, there is no partisan primary and all candidates are on every ballot.

*Expect to see a replay of the 2016 complaining from NPP voters in California who expect the county registrars to magically know they wanted the ballot with Bernie on it rather than the generic one. My county's already sent out the notice to NPP voters informing them and asking which of the 4 ballots they want.

We may get a few that are willing to do they, but they won't impact the outcomes on voting day.