Why can't Joe Biden, Kamala Harris, Pete Buttigeg, John Delaney, and other centrist democrats just run against Trump as Republicans?

These people aren't that much different policy wise then republicans are. The only difference is that they aren't bigoted or gun nuts.

In most countries, conservatives aren't racist, and they would be a fit for the conservative party in most other parties
Update: @Mike why do you think everybody to the economic left of Ronald Reagan is a socialist radical?
Update 2: @Lib nemesis:

* They ARE NOT FOR OPEN BORDERS. Not even the progressive wing of the democratic party support open border. BEING ANTI WALL OR ANTI ICE DOES NOT MEAN YOU SUPPORT OPEN BORDERS. The only major party in the US that supports open borders is the Libertarian Party
Update 3: * The Republicans are more anti-tax payer since they raise taxes for the poor and use the money for all sorts of corporate bailouts and unnecessary subsidies, and the oversized military budget. If you're going to tax people, spend it on projects the benefit the country as a whole (like a lot of what FDR did)
Update 4: * And while Kamala Harris did do stuff that hurt the minorities in the US when she was chief prosecuter (broken justice system), I highly doubt THAT was what you were thinking of when you called her racist
Update 5: @Anon(You think radical...) - You think that they're "left wing radicals" because they're okay with gay people and minorities and want separation of church and state. Conservatives in most countries generally agree with them on that, and if someone ran in most countries as an American Style Tea... show more @Anon(You think radical...) - You think that they're "left wing radicals" because they're okay with gay people and minorities and want separation of church and state. Conservatives in most countries generally agree with them on that, and if someone ran in most countries as an American Style Tea Party Christian Conservative, they wouldn't even get a single vote
Update 6: @jeeper - There are probably some libertarian-leaning Republicans who are pro-choice
Update 7: I needed 3 points and did not like the BA at all
10 answers 10