ASHINGTON -- As the top elected office in the nation's second-largest state, with a population and economy surpassing those of many nations, the Texas governorship might seem a rich source of experience for a presidential contender. George W. Bush certainly thinks so.

''There's only one person on this stage - only one person - who has been in a chief executive officer position in terms of government. That's me,'' Bush said in the Republican presidential debate Thursday night.

''I've got a record of leading ... the second-biggest state in the Union. If it were a nation, it would be the 11th-largest economy in the world,'' Bush said, returning to the theme at another point in the debate.

Yet there are reasons why no Texas governor has ever clinched a major party's presidential nomination or claimed the Oval Office. One may be that, unlike other states that have sent chief executives on to the presidency, Texas has a governor whose role, by constitutional design, is to be a relatively feeble public servant.

As governor of Texas, Bush is not allowed to appoint all the members of his Cabinet. He does not write the state's budget, and his ability to write legislation is limited by his constitutional authority and the fact that the Legislature meets only once every two years.

The impressive part of Bush's record is the political skill he has displayed in mounting an effective presidential campaign from a relatively powerless post, said former Texas congressman Charles Wilson, and not the broad or deep experience the governor earned during five years in office.

''It's probably the weakest governership in the country,'' said Wilson, a Democrat. ''It's riding in parades and appointing people to commissions.''

''The lieutenant governor has more power in Texas than the governor,'' said historian Arthur Schlesinger Jr., who once put the Texas governorship in a tie for last place when ranking the constitutional and legal powers of the 50 state executives. A similar survey by Congressional Quarterly ranked the Texas governor in 49th place.

A Texas governor's real clout is political, not constitutional, said William Stouffer, a political science professor at Southwest Texas State University. It is not Bush's experience as a powerful chief executive that the voters should weigh, said Stouffer, but rather the governor's ability to compensate for a lack of authority.

''If you look at the governor of Texas in terms of control over the budget, and control over the executive branch, and the ability to hire or fire people, it is analytically a weak governorship,'' said Stouffer. ''But being governor of Texas is not chopped liver. He has the attention of the national media ... and can use his office as a bully pulpit.''

Texans expect their governor to be a leader, employing the talents of an educator, salesperson, cheerleader, and lobbyist. Bush abounds in these qualities, which would also serve a president well, Stouffer said.

The governor has been adept at prodding the Legislature and at raising provocative issues for the lawmakers and public to consider. Without the power to coerce legislators, Bush has assiduously wooed them - particularly when striking an alliance with the former lieutenant governor, the late Bob Bullock, and House Speaker Pete Laney, both Democrats.

''Bush has been non-ideological for the most part,'' said Stouffer. ''He has worked with the Legislature more than previous governors. He is respected by most of the legislative leadership, Democrats and Republicans alike. He has used his limited powers and power of persuasion well and because of that he has got things done.''

Texas is indeed the second-biggest state in terms of population and geographic area, with a $600 billion diversified economy, a rich and proud culture, and such huge metropolitan areas as Houston and Dallas-Fort Worth. But Bush has presided in a time when the national economy was booming and the state had budget surpluses.

And in contrast to states that have full-time legislatures - like Massachusetts or California - the Texas Legislature meets every two years, for a 140-day session, sharply limiting a governor's opportunity to make a mark with policy initiatives.

After being elected in 1994, Bush lent his voice to ongoing political crusades for welfare, education, criminal justice, and tort reform, and for a measure that allowed Texans to carry concealed handguns. In each case he endorsed measures that legislators were already considering, pushed his own ideas, compromised when necessary, and signed the bills.

In another debate during his first term - over his far-reaching proposal for property tax reform in 1997 - Bush earned praise for taking a bold stand and educating the public about a simmering crisis, even though his plan failed to become law. Instead, he agreed to sign the Legislature's tax cuts, an experience he cited in the debate Thursday when saying, ''I want to remind the folks, I'm the one person up here who has signed a tax cut bill.''

Last spring, in his third legislative session, Bush faced setbacks when the Legislature pared his proposed $2 billion property tax cut by almost half, defeated his plan to let parents use vouchers to send their children to private school, and rejected a voluntary clean-air program he had negotiated with the state's industrial sector.

Nevertheless, Bush won passage of the pared-down tax cut and, when confronted with a Legislature that had decided to crack down on polluters, moved deftly to embrace the mandatory standards that the lawmakers favored, signing the legislation and claiming credit for those changes as well.

''I signed two really good pieces of legislation that are going to remove 250,000 tons of stuff being spewed in the air,'' Bush said Thursday. ''I've got a good record because I know how to set high standards; I know how to bring people together to achieve those standards.''

Chris Lehane, a campaign spokesman for Vice President Al Gore, contested Bush's claim. ''In Texas the decisions are made outside the governor's reach,'' Lehane said.

The quirks in the Texas political system date to the Reconstruction period that followed the Civil War, when radical antislavery Republicans ruled the Southern states. When the state adopted its post-Reconstruction constitution in 1876, it was explicitly designed to curb the central authority that Republican Governor Edmund Davis had abused. The Texas constitution - six times longer than the US Constitution and amended more than 200 times since - disperses power.

It is not the governor of Texas, but the Legislature - through the powerful Legislative Budget Board - that writes the state budget and funds government programs, pork-barrel projects, and other political plums.

In other states the lieutenant governor is a subordinate, consigned to the governor's shadow. But in Texas the lieutenant governor presides over the state Senate, controlling the legislative schedule, assigning bills to committee, and determining what measures reach the floor. Because the lieutenant governor is elected independently, he or she may be from the opposing political party, adding to a governor's headaches.

Cabinet secretaries generally serve at the pleasure of their governors. But in Texas the state's executive powers are dispersed among commissioners - like the agriculture and land commissioners - who are directly elected by the people, and among a variety of boards and commissions whose members are appointed by the governor with the Senate's approval.

The governor's primary statutory powers are vetoing legislation and appropriations and calling special sessions of the Legislature.

''Really, the main power the governor has is to veto bills, especially after the Legislature has gone out of session, when there is no mechanism to override his veto,'' said Suzy Woodford, the executive director of Common Cause of Texas, a public interest group.

Yet Schlesinger, a lifelong scholar of the presidency, said the artificial yardstick of ''experience'' can prove misleading. ''Much more depends on the man than the office he holds,'' he said.