President Barack Obama on Tuesday used the bully pulpit of a midday White House news conference to tout his health care agenda, but he appeared to show flexibility on controversial issues like universal coverage and a government insurance option.

His opening statement — which covered health reform, Iran and the House energy bill — was as notable for what it didn’t address on health as for what it did: The prepared remarks focused almost entirely on cost and failed to mention either a public option or expanding coverage.

Asked if his insistence on a public plan was “non-negotiable,— his initial answer was, “Chip,— as he moved on to the next questioner, Chip Reid of CBS News. When pressed by another reporter, Obama said, “Right now I will say that our position is that a public plan makes sense.—

In answer to another question, Obama said that the only “line in the sand— he has drawn is that a bill must lower costs and provide “relief— for those who don’t have coverage or are underinsured

In his speech to Congress in February, Obama’s remarks were more forceful. In discussing health care reform, he touted “the principle that we must have quality, affordable health care for every American.—

Obama said Tuesday that his “top priority— is controlling health care costs. “If any bill arrives from Congress that is not controlling costs, that’s not a bill I can support,— he said. “Its’ going to have to be paid for,— he added.

Likewise, with Congress apparently falling behind schedule in its consideration of health reform legislation, Obama did not try to enforce a timetable.

“I hope that Congress will continue to make significant progress on this issue in the weeks ahead,— he said.

While he didn’t insist on a government insurance option, the president was vigorous in his defense of it, denying that it would lead to a government “takeover— of the health system. But Republicans gave the argument a thumbs down.

“Today the President again claimed that the Democrats’ government takeover of health care would not force Americans off of their current plans, yet independent analysts have reported that at least 23 million Americans would lose their coverage under the bill drafted by Senate Democrats,— House Minority Leader John Boehner (R-Ohio) said in a statement released after the press conference. “House Republicans have introduced a better alternative to make health care more affordable and accessible, ensure that Americans can keep their health plan, and keep doctors and patients, not government bureaucrats, in charge of critical and personal medical decisions.—

With his other top priority — an energy bill with a carbon emission cap-and-trade program — now headed for a possible vote in the House by week’s end, Obama thanked Democratic leaders for their work and offered strong backing for the legislation.

“It’s a bill that will open the door to a better future for this nation, and that is why I urge Members of the House to come together and pass it,— he said.

The president offered his strongest remarks to date on Iran amid growing criticism from Republicans and others that he has been too restrained. But he denied his statement was in response to criticism from Sen. John McCain (R-Ariz.), and he took a moment to remind his erstwhile opponent who won the election.

“Only I’m the president of the United States,— Obama noted, suggesting that his position forced him to look at a broader picture than critics who could carp from the sidelines. “I’ve got responsibilities … to make sure we are not used as a tool to be exploited by other countries,— he said of the tempered approach to Iran he has used so far.

Obama also applauded Federal Reserve Chairman Ben Bernanke for his response to the economic crisis, but he declined to commit to reappointing him.

The president said a second stimulus bill was not yet needed, suggesting Congress should allow the first stimulus bill to play out further and see how the economy does.

And, a day after signing the tobacco bill into law, Obama acknowledged that he still smokes occasionally, though not every day and not in front of his children. “I would say that I am 95 percent cured, but there are times I mess up,— he said.