It’s back to the House with the health care bill.

Early this morning, Republicans identified parliamentary problems with the package of changes to the Democrats’ sweeping overhaul of the health insurance system, forcing the House to take a second vote on the legislation after the Senate approves it.

Senate Democrats were on an all-night crusade to defeat scores of Republican amendments in what aides and the Congressional press corps termed a “vote-a-rama.” But after defeating two dozen changes to the legislation, the Senate parliamentarian ruled that the bill did not meet the complex budget reconciliation rules requiring all provisions to directly affect government spending or revenues. The snag, however, did not appear to endanger the eventual adoption of the changes, The Times’ David Herszenhorn and Robert Pear write.

Senator Kent Conrad, Democrat of North Dakota and chairman of the Budget Committee, said the Senate would complete work on the bill by 2 p.m. today even though lawmakers did not leave the floor until around 2:55 a.m. this morning.

Promoting the Bill: The stumping never stops. President Obama makes his way to Iowa today to promote his health care bill as Democrats begin a public relations campaign to win over skeptical Americans. He’ll address a group at the University of Iowa at 1 p.m. Central time.

Vote Backlash: But anger over the bill and the parliamentary maneuvering used to pass it may run deeper than Democrats expected. Lawmakers who voted for the bill have received death threats and been the victims of vandalism.

At least 10 House members have raised concerns about their personal safety on the heels of a tense weekend in which protesters hurled slurs at Democratic lawmakers approaching the Capitol Building. All of this spells political trouble for Republicans as they push for a repeal of the bill and use it to build momentum for the midterm elections.

“The dark and personal tone of the final stages of the health fight could complicate Republican efforts to maintain their attacks on the legislation if they are seen as inciting an undue level of outrage and, conversely, could bolster Democrats if opponents of the measure are seen as breaching the boundaries of civility,” The Times’s Carl Hulse writes.

Public Option, Take Two: Democrats have pledged to resist a final push for a government-run insurance plan from liberal advocates and — in the face of a rare opportunity to make it law by a simple majority — will choose instead to take their winnings and call it a day, The Times’s David Herszenhorn writes.

The public option’s last gasp illustrated an aching contradiction for Democrats at the heart of the reconciliation bill. In one chapter, the bill kicks private banks out of the federal student loan business, on a belief that government can do just as good a job and that the profit-motive of the private sector is only getting in the way.

At the same time, the bill preserves and expands the existing private health insurance industry, bowing to Republicans and some Democrats who argued that the private sector was more efficient and effective than the government could ever be.

Liberals with their hearts still set on a public option, however, are considering offering a second budget reconciliation measure to establish the program after the current health care bill is completed, Senator Tom Harkin, the chairman of the Health, Education and Labor Committee told The Hill newspaper. Like the House-approved fix-it measure, the bill would only need a simple majority to pass.

But what if a Republican senator offered the public option as an amendment today? That would put Democrats in the awkward position of having to vote against the government run plan to protect the bill’s integrity. If they did vote for it, they risk not being able to rally the votes in the House, explains Mr. Herszenhorn.

Ad Wars: Look out for a new string of advertisements targeting vulnerable Republicans starting today and running through next week. The Democratic National Committee has doubled its hit list from five Republicans to 10 since the health care vote, Politico reports.

Social Security on the Brink: As Republican criticism over spending continues, another safety-net program, Social Security, will end up paying out more in benefits than it receives in payroll taxes this year, six years before it was expected.

Speaking of job loss, the Labor Department releases its weekly report on unemployment insurance claims at 8:30 a.m.

Russian Nuclear Deal: Mr. Obama and his Russian counterpart, President Dmitri A. Medvedev, have reached an agreement to slash their nuclear arsenals to the lowest levels in half a century. The 10-year pact, which they expect to sign next month, is perhaps Mr. Obama’s most significant foreign policy achievement since he took office, The Times’s Peter Baker and Ellen Barry write.

Under the new pact, according to people briefed on it in Washington and Moscow, within seven years each side would have to cut its deployed strategic warheads to 1,550 from the 2,200 now allowed. Each side would cut the total number of launchers to 800 from 1,600 now permitted. The number of nuclear-armed missiles and heavy bombers would be capped at 700 each.

Don’t Ask, Don’t Tell: Secretary of Defense Robert M. Gates will announce plans to make it more difficult for the military to expel openly gay service members, an interim plan while the Pentagon examines repeal of the “don’t ask, don’t tell” policy, in a news conference at 9:30 a.m.

Census: Just about 20 percent of Americans have completed and returned their 2010 census, but lawmakers are already focusing on the next round. Representative Carolyn B. Maloney, Democrat of New York, and Senator Thomas R. Carper, Democrat of Delaware, will introduce a bill aimed at giving the Census Bureau, now housed within the Commerce Department, more political and budgetary Independence at 11:30 a.m. today at the Capitol.

The Times’s Dan Barry has this piece on one woman’s mission to have her town of San Antonio in central Florida completely counted.

Clinton’s Day: Today is the second day of a conference between American and Pakistani diplomatic leaders — the first “strategic dialogue” between the two countries at the foreign minister level, as the State Department describes it.

Secretary of State Hillary Rodham Clinton is the guest of honor at a celebration for Congressional Women’s History Month on Capitol Hill at 12:15 p.m. Then, Mrs. Clinton and Secretary of Defense Robert M. Gates testify before the Senate Appropriations Committee about the supplemental budget the administration has requested to fund the wars in Iraq and Afghanistan.

BFD: It’s safe to say Vice President Joseph R. Biden Jr. wasn’t thinking of the Obama administration’s next viral branding campaign when he whispered a certain expletive into Mr. Obama’s ear at the health care bill signing ceremony Tuesday. But, now Mr. Biden’s BFD moment is emblazoned forever on T-shirts, domain and Twitter names. Urban Dictionary even made “BFD” the term of the day Wednesday.

Mr. Biden told a crowd at a fund-raiser in Baltimore Wednesday night that the president wanted to order one of the T-shirts, according to a pool report.

“You know what the best thing about yesterday was? Joe’s comment,” Mr. Obama said at the morning presidential briefing, according to Mr. Biden.