The reason he wasn’t re-elected in 1988 was the apparent violation of his “No New Taxes” pledge.
But: Although he did oppose the creation of new taxes as president, the Democratic-controlled Congress proposed increases of existing taxes as a way to reduce the national budget deficit. Bush negotiated with Congress for a budget that met his pledge, but was unable to make a deal with a Senate and House that was controlled by the opposing Democrats. Bush agreed to a compromise, which increased several existing taxes as part of a 1990 budget agreement. That was not a “New” tax but and increase in an old tax. The voters choose to elect Bill CLinton and that caused a lot of harm to America. The harm is still going on with Hillary still yapping around.