If Republican donors want to vote person, not party or want to vote against their party's pick (say Trump) it's perfectly fine for them to donate to the campaign of another candidate outside the party. It can be because they believe in a specific candidate or because they feel they have no other choice but to go outside the party.
It would be amazing if democrats and republicans came together to stop Donald Trump from taking over the country with his insanity. We have to stop seeing each other as adversaries and realize that we need each other. Yes, "we the people " is for all of us. We have to keep the country from going back to wars we can't win, record unemployment, a stock market in swift decline, people losing their businesses and homes etc. Let's face it, the good old days were not that good.
Republican donors should not contribute to democratic candidates campaigns because that would help them get defeated. In every campaign, money is needed to win. With republican donors donating to them, they can spend less time on fund raising and more time on the campaign trail campaigning. This would make it harder on republican candidates to win.
Republican donors should contribute to any of the three Republican candidates - Trump, Cruz or Rubio rather than contributing to the Democratic candidates Clinton and Sanders for their campaign.
I dont think the Republican donors should contribute to Democratic candidates campaigns. This wouldnt be of any use for the Repubican donors