WASHINGTON—The White House is urging congressional Democrats to engage Republicans in a fight over taxes, pressing them to go on the offensive after the Supreme Court's health care decision gave prominence to the issue.

White House senior adviser David Plouffe is sending a memorandum to the House and Senate Democratic caucuses saying Republicans are misrepresenting Obama's record. In a memo obtained by the Associated Press, Plouffe said the White House welcomes a debate on taxes.

Obama has called for tax increases on households earning more than $250,000, but has also said existing tax cuts should be extended permanently for the middle class.

The court upheld the law, declaring that a penalizing people who can afford insurance but don't buy can be treated as a tax.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

The White House is pushing back against questions about whether President Barack Obama's health care law would mean new taxes for many people.

A day after the Supreme Court upheld the law, White House press secretary Jay Carney says the law will create a "penalty" that will affect about 1 percent of those who refuse to get health insurance.

He says the penalty was modeled after the one put in place in Massachusetts when Republican Mitt Romney was governor. Romney is now Obama's presidential challenger.

The "tax" versus "penalty" label is important

because the court said the penalty essentially is a tax, and that's why the government has the power to impose it.

Republicans have said the health care law will amount to a large tax increase for many people.