CAIRO » President Hosni Mubarak came to power amid crisis three decades ago, a reassuring symbol of stability for many Egyptians as well as for Western leaders seeking a solid ally in the Middle East. Today, crisis again envelops Egypt, and Mubarak is widely seen as the root of the problem.

In the span of his presidency, Mubarak, a former pilot and air force general with a combative, stubborn streak, took tentative steps toward democratic reform but then pulled back toward the authoritarianism that, coupled with poverty and a culture of corruption, helped drive Egyptian protesters into the streets.

The prospect that Mubarak was grooming his son, Gamal, to succeed him left many Egyptians feeling that they were trapped in the past, deprived of the opportunity for change and renewal. Then, the uprising in Tunisia delivered an electrifying message: An old order can be ousted.

The message of protesters massed in Cairo’s main square for several days is a stark departure from the praise Mubarak had once won for keeping Egypt free of the grip of Islamic extremism, and solidly allying with the West amid wave after wave of Mideast crises.

His ascent to power — he was sitting on a military viewing stand next to his predecessor, Anwar Sadat, when Sadat was assassinated by Islamic militants — recalls the welcome legacy of his early years.

On the whole, his serious, cautious image reassured many Egyptians.

His political credibility, however, has suffered irreparable damage. That vulnerability, at least in hindsight, goes back decades. He lacked the charisma of his legendary predecessors — the peacemaker Sadat and the great nationalist Gamal Abdel Nasser — and constantly served in their shadows.

He also struggled constantly with the problems that have bedeviled much of the Arab world through modern history: economic stagnation, choking corruption, the Palestinian-Israeli conflict and fighting Islamic militancy at the expense of personal freedoms.

As the years went by, Mubarak also became more aloof, choreographing his public appearances, and his authoritarian style appeared increasingly out of sync with a world focused on political openness.

More seriously for the West, Mubarak oversaw the wane of Egypt’s regional influence in recent years as the militant groups Hamas and Hezbollah and their patron, Iran, gained momentum and followers.

Mubarak was serving as Sadat’s vice president when Muslim extremists gunned down the president in 1981, killing the world’s best hope for Arab moderation. Egypt’s parliament designated Mubarak the sole presidential candidate the next day, and he was elected head of state on Oct. 13, 1981, with 98.5 percent of the vote.

Early on, Mubarak strongly put down the Muslim militant insurgency whose strength had been underestimated, and whose ranks had produced Sadat’s assassins and some of the future leaders of al-Qaida.

Mubarak engineered Egypt’s return to the Arab fold after nearly a decade out in the cold over its 1979 peace treaty with Israel, and carved himself a role as a major mediator in the Arab-Israeli peace process.

He also made moves that promised he would open up society and that won him considerable popularity at home — including freeing 1,500 politicians, journalists and clerics jailed during Sadat’s last months.

But hopes for broader reform dimmed as, through the years, Mubarak was re-elected in staged, one-man referendums in which he routinely won more than 90 percent approval.

Yet throughout, Mubarak remained a strong ally of the United States, carving out a niche as a key negotiator on the Palestinian crisis and bolstered by billions in U.S. aid because of his country’s ties to Israel.

"It is a very tough job," Mubarak once told an interviewer. "All you seem to do is wake up to trouble and sleep to trouble."