Bush made that promise, and worked hard to keep it, but eventually when he was just making no progress on deficit reduction with the Dem House and Senate he gave in, and taxes increased and most of the promised cuts never materialized. There's lots of precedent these days, sit down with the Dems and compromise for $1 in tax increases for $3 in cuts and what you'll get at best is $3 in increased for $1 in cuts and usually $3 in increases for $4 in new spending instead. So not only do they know they'll be held to account by their voters they also know that agreements to cut some spending for a some tax increases materialize rarely and even then only it scrawny bastardized for m of what was agreed to.