Thomas S. Foley, the speaker of the House who became the ­highest-profile casualty in the Republican “revolution” of 1994, the election that ended the Demo­cratic Party’s hammer­lock on the chamber and signaled the start of a furious new era in political warfare, died Oct. 18 at his home in Washington. He was 84.

His wife, Heather Foley, confirmed the death and said the cause was complications from strokes. The Washington state congressman had been ailing from conditions including pneumonia.

Mr. Foley was one of Capitol Hill’s most outspoken critics of the extreme partisanship that emerged toward the end of his career, which contributed to his defeat in the 1994 election and has since intensified so dramatically that Congress is often described as “broken.”

He was elected to the House in 1964 and served for 30 of the 40 consecutive years that his party controlled the chamber. Mr. Foley established himself from the outset as a conciliatory figure; one of his first acts after his election victory was to host a reception for the Republican incumbent he defeated to win the seat.

As he rose through the leadership ranks — from majority whip to majority leader and finally to speaker in 1989 — he became known as a consensus builder.

He helped forge a compromise that allowed the deficit-reducing Gramm-Rudman-Hollings legislation to go through in the mid-1980s. He publicly supported President Ronald Reagan, a Republican, on his controversial economic strategy. During President Bill Clinton’s administration, Mr. Foley helped him win passage of the North American Free Trade Agreement despite opposition from many other Democrats.

He was a burly man with a commanding physical presence, but especially as speaker he did not seem to relish power. “There is a degree to which you can sort of push, encourage, support, direct,” he once told the New York Times. “But the Speakership isn’t a dictatorship.”

That outlook separated him from Thomas P. “Tip” O’Neill Jr., the powerful, back-slapping Massachusetts liberal who presided over the House in the late 1970s and through most of the 1980s, and from Jim Wright, the Texas Democrat who succeeded O’Neill and was criticized for heavy-handedness.

By the later years of the Democratic majority, the party was increasingly perceived to have grown arrogant with power. Then Rep. Newt Gingrich of Georgia, the future speaker of the GOP-controlled House, seized on the resentment to launch what became known as the Republican revolution.

One of his chief tools of political warfare — later wielded against him — was the ethics inquiry. His most prominent target was Wright, who resigned from Congress in 1989 amid a polarizing investigation into his book sales and personal business dealings.

Mr. Foley, then majority leader, succeeded Wright as speaker. For two more election cycles the Democrats held the House, but Republican momentum, fueled by Gingrich, was building. In the 1994 election, Mr. Foley was painted as a Washington insider — the figure­head of the unpopular Democratic House — and buffeted by calls to “De-Foley-ate Congress.” When he lost, he was the first House speaker to be unseated since Abraham Lincoln was president.

Major role in spite of himself

A grandson of homesteaders and son of a judge, Mr. Foley sometimes seemed out of place in the rough-and-tumble of Capitol Hill politics, even as he ascended to become, as House speaker, second in line of succession to the presidency. The New Yorker magazine once described him as a “major player almost in spite of himself.”

He won his House seat by defeating an 11-term Republican, Walt Horan, in a conservative district in eastern Washington state. Mr. Foley had not registered his candidacy until minutes before the filing deadline because he was not entirely convinced that he wanted to run.

In the nation’s capital, he joined other Democrats in leading the series of historic reforms that reordered the House by dismantling its seniority-based system and decentralizing power among the subcommittees and individual members.

Mr. Foley stood to benefit from those reforms in 1975, when colleagues moved to replace entrenched chairmen including W.R. Poage (D-Tex.) of the Agriculture Committee. Mr. Foley, then the committee’s second-ranking Democrat, refused to partake in Poage’s ouster and instead rose to his defense. When Mr. Foley was elected chairman, he named Poage vice chairman.

“It was an extraordinary moment in House history,” former congressman Don Bonker (D-Wash.) told The Washington Post years later, remarking on the collegiality Mr. Foley had displayed.

After the 1980 election, Mr. Foley gave up the committee chairmanship to become majority whip. He drew wide attention in 1982, when he gave a televised speech calling on Democratic colleagues to cast a vote of “political courage” to support Reagan’s tax proposal.

“A star is born,” O’Neill, a political kingmaker as speaker, was quoted as saying shortly there­after in admiration of Mr. Foley’s performance.

As majority leader, a post he assumed after the 1986 election, Mr. Foley became part of the troika that included Wright and Rep. Tony Coelho (D-Calif.), the party whip. Mr. Foley stood out as decidedly the least partisan of the three.

Some prominent Democrats expressed frustration with what they considered Mr. Foley’s excessive caution at a time when Republicans, led by Gingrich, appeared to be on the march. O’Neill was widely reported to have said that Mr. Foley could “argue three sides of every issue.”

“When you talk to Tom, you start biting your fingernails and you don’t stop until you’re up to your elbows,” former congressman Dan Rostenkowski, the powerful Illinois Democrat, once told Time magazine. “What he does is good, but sometimes getting there is frustrating.”

Characteristically, Mr. Foley acknowledged his critics’ points. But, he once told the New York Times, “I guess I don’t think caution is a bad attribute.”

“I do look at problems from as many sides as possible,” he said. “I concede that. I say, ‘What about this? What about this?’ That’s how I decide what the best course should be.”

H is speakership

Mr. Foley’s speakership began with what was roundly described as an episode of unscrupulous partisanship.

At the time of his selection, the Republican National Committee released a memo titled “Tom Foley: Out of the Liberal Closet.” In what was described as an effort to cast doubt on Mr. Foley’s reputation as a moderate, the memo compared his voting record to that of Rep. Barney Frank (D-Mass.), a liberal legislator who was openly gay.

Legislators on both sides of the aisle condemned the memo and its innuendo. Mr. Foley appeared on television and said that he was “of course, not a homosexual, been married for 21 years.”

Lee Atwater, the RNC chairman, apologized to him. President George H.W. Bush called the memo “disgusting.”

Despite the ongoing infighting, the House achieved a number of legislative milestones during Mr. Foley’s speakership, which spanned five and a half years, from the early months of the George H.W. Bush administration through the first half of Clinton’s first term.

During the Bush years, Mr. Foley presided over the House during the passage of a landmark update to the Clean Air Act, expansions of the Head Start and Medicaid programs, the Americans With Disabilities Act and, most notably, the massive 1990 budget deal that established “pay-as-you-go” practices. That legislation forced Bush to break his “no new taxes” promise — a key issue in his 1992 reelection defeat — and split the Republican Party, with Gingrich leading the opposition.

During the Clinton administration, Congress passed a second massive budget deal that laid the groundwork for balancing the budget but stirred controversy because of the tax increases it imposed. Other legislative milestones, besides NAFTA, included passage of the Family and Medical Leave Act.

But the “primary significance” of his speakership, said Thomas E. Mann, the congressional scholar, was Mr. Foley’s leadership at a time of such turbulence in the House.

“It was a time when the House was unraveling,” he said, “and so it was a very difficult period, especially for someone like Foley who had . . . such respect for the institution and reverence for it.”

Mr. Foley’s Republican challenger in the 1994 election, George R. Nethercutt, benefited from Mr. Foley’s association with the deeply unpopular Congress. Contributing to voter dissatisfaction was the House banking scandal, in which it was discovered that members had been permitted to overdraw their accounts in the House bank. Mr. Foley was accused of responding ineffectively to the issue.

His district became a microcosm of all the turmoil and rancor in American politics — including, prominently, the widespread and heated debate over whether House members should be bound by term limits. In his campaign, Nethercutt highlighted Mr. Foley’s lawsuit challenging a ballot initiative setting such limits.

“I would never sue my constituents to save my job,” Nethercutt said in one campaign commercial. He won by about 4,000 votes.

Mr. Foley told reporters at the end of his speakership that, if he had any regret, it was that he had not conveyed “as effectively as I hoped we might, the work we do and some of the achievements that we have made and accomplished in this Congress.”

Nicknamed ‘the senator’

Thomas Stephen Foley was born March 6, 1929, in Spokane, Wash. While attending a Jesuit preparatory school, he was nicknamed “the senator” for his intellectual, methodical demeanor. The New York Times once reported that he defeated a lisp to become a top debater. He received a bachelor of arts degree in 1951 and a law degree in 1957, both from the University of Washington.

Mr. Foley practiced law in Spokane before becoming a prosecutor and, later, assistant state attorney general. He became involved in politics through Sen. Henry M. “Scoop” Jackson (D-Wash.), who in 1961 hired him as a special counsel on the Interior and Insular Affairs committee and later encouraged him to pursue elective office.

While working for Jackson, Mr. Foley met Heather Strachan. They were married in 1968, by which time Mr. Foley had been elected to Congress. For years she worked as his unpaid administrative assistant and at times drew attention for the power she wielded on Capitol Hill. In one oft-recited episode, she dared to ask then-Speaker O’Neill during a meeting to put out his cigar. (He did.)

Besides his wife, survivors include a sister.

In his early years on Capitol Hill, Mr. Foley opposed the escalation of the Vietnam War and supported the Great Society programs of President Lyndon B. Johnson, who won a landslide victory the same year Mr. Foley joined the House.

Mr. Foley said in 1989 that, of his legislative achievements, he was most proud of his work on the Agriculture Committee to advance the food stamp program. He was credited with forging a partnership between advocates for farmers, who tended to be conservative, and advocates for increased social programs.

In 1997, Clinton selected Mr. Foley as U.S. ambassador to Japan, a post he held until 2001. In recent years, he lived largely out of the public spotlight in his home in the Capitol Hill neighborhood, not far from the chamber that he had led through one of the most tumultuous periods in its history.

He once reflected poignantly, and presciently, on the nature of political life.

“Sometimes I think it looks like it’d be fun to be committed in that sort of unreserved way to something — to have a life work about which there are no doubts,” he told the New York Times in 1990. “I sometimes envy people in the House who are engaged in stopping something. Most of my Congressional career, I’ve had to try to put together coalitions of support or worry about moving legislative efforts. . . . It’s a lot easier to blow up the bridges and to block the crossings.”