Here are some numbers that you need to remember as you watch President Barack Obama and Congress wrangle over a blizzard of figures at the heart of a proposed dramatic overhaul of the way Americans receive their health care: 372-33, 77-6, 307-116 and 70-24.

These numbers are vital to understanding the American political system, if not the American medical system, and anyone who overlooks them is forgetting an important quality of the way Americans have governed themselves and cared for themselves as they grow old and infirm.

Earlier initiatives

So brace yourself for some sobering math. The original Social Security bill, as dramatic a departure from the American economic way as any in our history, passed the House on April 19, 1935, by a 372-33 vote and passed the Senate exactly two months later by a 77-6 vote. The Medicare legislation, which built on the Social Security precedent and is a predicate for Obamacare, passed the House on July 27, 1965, by a 307-116 vote and was approved by the Senate a day later on a 70-24 vote.

Why should that ancient history be of concern to President Obama and Congress today?

Easiest question of the week. Because Social Security and Medicare, the 1935 and 1965 stepping stones to Obamacare in 2009, were among the most significant pieces of social legislation ever to win congressional approval. They passed by large margins, big enough so that history would record that Presidents Franklin D. Roosevelt and Lyndon B. Johnson had developed a broad and lasting consensus for these initiatives.

These votes assured that Social Security and Medicare were regarded as mainstream landmarks in American social history. As a result, these two remarkable programs swiftly became accepted as unremarkable aspects of American life.

Today, Medicare attracts the concern not of opponents but of accountants, their worry being the demographic changes that imperil perhaps America’s most popular health program. And in the three-quarters of a century in which Social Security has been a cornerstone of Americans’ financial planning, only one major political figure, Sen. Barry Goldwater of Arizona, has mounted an all-out assault on the program. He lost 44 states in his 1964 presidential campaign against Lyndon Johnson, who a year later was able to celebrate the triumph of Medicare.

But, you might argue, didn’t both Roosevelt and Johnson have huge congressional advantages? Well, yes. Roosevelt had 319 Democrats in the House, Johnson 293. FDR had 69 Democrats in the Senate, LBJ 68. Those are very big margins.

Bipartisan support

But what matters is this: A majority of Republicans in both houses supported Social Security in 1935 and a majority of Republicans in the House supported Medicare in 1965. (The Medicare legislation in the Senate failed to win a Republican majority by only four votes.)

Let’s hope Washington keeps this in mind. Lawmakers and the administration should measure today’s health-care overhaul against Social Security and Medicare, see that it represents an even more dramatic change in the American landscape than either of those individual programs, apply the lessons of 1935 and 1965 to 2009, and recognize that you don’t change the way Americans live on a narrow partisan vote.

Until late last week, when congressional negotiations made important headway, Washington was sliding toward a partisan confrontation that would endanger Obama’s greatest domestic priority and his commanding position in the capital. Even so, the president is not flirting with the kind of humiliation and destruction created by the Clinton health-care debacle a decade and a half ago.

Bill Clinton was forced to abandon his top campaign promise in 1994 when the health-care initiative headed by Hillary Rodham Clinton so alienated Congress that the administration was forced to abandon it, setting up an even more mortifying defeat in the midterm congressional elections, when the Republicans gained control of both Houses of Congress for the first time in four decades.

Despite last week’s progress, Obamacare still might win congressional approval largely on a partisan basis — which would give Obama a victory, but perhaps only a pyrrhic one. He wouldn’t be in the hall of humiliation occupied by Clinton, but he also would not win a place in the pantheon that includes Roosevelt and Johnson.

Clinton and Obama are unusual among American presidents in that they won office having campaigned on dramatic policy changes. (Johnson did so in 1964, but he was running from the White House, not as a presidential aspirant.) Many of the great American presidents, including Franklin Roosevelt and Abraham Lincoln, won the presidency without detailing major policy proposals. For Roosevelt and Lincoln, the charge was to deal with a national crisis, and both offered styles rather than specifics in their campaigns.

Presidential agendas

Historical oddity: The only president who set out dramatic specifics and achieved them in the White House may have been James K. Polk, who between 1845 and 1849 sought to establish an independent Treasury system for government funds, win a tariff reduction, acquire Oregon (then the subject of a contentious border dispute with Great Britain) and obtain California and New Mexico (from Mexico). He was 49 when he took office. Obama turns 48 Tuesday.

Are all the signs gloomy? No. The Democratic congressional leadership is spooked by the restiveness some House Democrats displayed following the climate-change vote last month and show signs of reaching out to moderates. And if you look carefully at the six Senate sachems who are emerging as the principals in the health-care fight, you will see that one of the Republicans is Sen. Charles E. Grassley of Iowa, who dearly wants a compromise.

Another is Sen. Olympia J. Snowe of Maine. She’s perhaps the most reasonable member of the Senate of her generation, heir to both Margaret Chase Smith, a Republican, and Edmund S. Muskie, a Democrat. Her degree from the University of Maine at Orono may be in political science, but she is an expert in psychology — and math. My guess is that she knows the meaning of 372-33, 77-6, 307-116 and 70-24.