In his first six months in the White House, President Barack Obama has seen his approval ratings slip about 10 percentage points as he takes on a battered U.S. economy.
Obama, insisting the "stars are aligned" for approval this year despite discord in Congress over the plan, warned inaction would undermine the economy, worsen the deficit and cripple millions of Americans financially.
"I understand people are feeling uncertain about this. They are feeling anxious," he said in a prime-time televised news conference.
But he said he was confident people would support it when they looked "at the cost of doing nothing."
The healthcare debate is reaching a critical juncture in the Democratic-controlled Congress. Obama wants both the House of Representatives and Senate to vote by early August but many lawmakers want more time to consider such an expansive set of proposals.
Several polls show Obama's job approval rating dropping and that Americans are having doubts about his prescriptions for the economy and healthcare.
Obama said people were "understandably queasy" about government spending and the debt piling up, but argued the health of the economy depended on stemming healthcare costs, which account for 17.6 percent of gross domestic product.
"That is why I've said that even as we rescue this economy from a full-blown crisis, we must rebuild it stronger than before. And health insurance reform is central to that effort."