MOSCOW — It looked as though Vladimir V. Putin had been gearing up to push through obscure constitutional changes as a surreptitious way to remain Russia’s leader after presidential term limits forced him to step down in 2024. But on Tuesday, Mr. Putin endorsed a proposal stunningly simpler and more brazen: resetting the Constitution’s term-limit clock to zero.

The proposal, passed by the lower house of Parliament just hours after it had been introduced, would allow him to serve for an additional two six-year terms when his tenure expires.

The legislation must still be approved by Russia’s Constitutional Court and a nationwide referendum in April. But in Russia’s tightly controlled political system, the choreographed flurry of events on Tuesday was the clearest sign yet that after 20 years as president or prime minister, Mr. Putin, the 67-year-old former KGB spy and icon of strongman rule, is intent on staying in the Kremlin possibly for the rest of his life, or at least until 2036.

If he serves until then, Mr. Putin will have held the nation’s highest office for 32 years, longer than Stalin but still short of Peter the Great, who reigned for 43 years.