President Bush has privately vowed to veto any legislation that would expand children’s health insurance by increasing taxes on tobacco. Officials say Bush made the pledge at a closed-door meeting Tuesday with Republican lawmakers at the White House. Bush is also said to have strongly suggested he will not sign legislation that includes any tax increase, such as the energy bill currently before Congress. Bush’s comments mark a hardening of his showdown with Democrats over expanding the State Children’s Health Insurance Program, known as S-CHIP. Bush vetoed a bill increasing S-CHIP funding earlier this month.