George W. Bush's presidency did no exactly "harm" the Republican party, but it did strengthen the democratic party. He may not have been a bad presidents, times might not have been any better under another president. Bush's presidency though, since it was negatively viewed by much of the country, hurt the republican party because he is affiliated with that party. One person cannot destroy or turn around a party, it takes years. Bush's presidency happened to have many bad breaks and decisions which led to the uprising of the democratic party.