Former President Ronald Reagan vetoed nearly 70 bills; George H.W. Bush used his veto power 44 times. Other presidents have exercised their authority over the legislative branch hundreds of times.

But despite a number of threats, President Bush's record on vetoes so far -- none, zip, nada.

That restraint has some analysts wondering whether the president will employ his veto power to demonstrate his strength before the next presidential election. Others say the fact that he has not vetoed any bills shows his power and deftness in working with a Republican-dominated Congress.

"The greatest power of the veto is not in its use but in its threat. [Bush] has threatened it many times, and it has modified the legislation," said Larry Sabato, director of the University of Virginia’s Center for Politics (search).

Michael Genovese, professor of political science at Loyola Marymount University in Los Angeles, said Bush has managed to avoid using the veto because "of his ability to largely dominate the congressional agenda."

The veto is "an instrument best left unused. You use it when you have not succeeded. Some people see [using] it as a sign of strength, but in strategic political terms, it’s a sign of weakness when you have to use it a lot," Genovese said.

Experts suggest that Republicans Reagan and the first President Bush used the veto with occasional frequency because they were squaring off against an opposition Congress.

For part of his term, former Democratic President Bill Clinton also faced a Congress run by the opposition party, leading him to veto such GOP legislation as the repeal of estate taxes, the so-called marriage penalty and the "partial-birth abortion" bill that looks set to become law soon under the current president.

The veto is used most often when a president has to work with a Congress that is dominated by the other party, said Heritage Foundation (search) fellow Lee Edwards, a presidential scholar.

"I think that’s why [Bush] has been sparing it," Edwards said. "At the same time, I think sometimes you have to use a veto and that sends a message to both your own party and the opposition party."

Experts are wondering which legislation Bush would veto. The White House has said the president is inclined to veto a bill that would overturn new media ownership rules recently promulgated by the Federal Communications Commission (search).

Among other legislation, threats have circulated around the "Buy American" provision of the Defense appropriations bill, as well as a measure that would block the White House from changing the rules on overtime pay that now protect middle-income workers seeking to collect time-and-a half pay.

This month, both chambers ignored veto threats. The House and Senate have both passed legislation blocking changes to the current overtime pay laws. The House also passed an amendment to the Transportation and Treasury Departments' funding bill that would ease travel restrictions to Cuba.

American Enterprise Institute research associate John Fortier noted that with the president’s popularity sliding and Congress defying him, he is more likely to veto legislation.

"As he’s weaker, I think he’s going to have to rely more on the veto," Fortier said.

Bush’s poll numbers have slipped, with his approval rating dropping to 53 percent, according to a recent Fox News/Opinion Dynamics poll. In an August poll done by Fox News/Opinion Dynamics, Bush's approval rating was at 61 percent. Earlier polls showed even more support for the president.

For this reason and because the presidential election is approaching, Democrats are likely to push the administration harder on certain bills. Some centrist Republicans on Capitol Hill are also less likely to follow Bush’s lead and more likely to test him because of his lower popularity, say the experts.

"I think there’s always a danger of using a threat and then not carrying it out, so maybe there needs to be a little lowering of the rhetoric there," Edwards said, adding the caveat that he "wouldn't be surprised" to see a veto on the horizon.

Bush "will certainly veto legislation if it does not meet his standards and priorities as he has indicated he would," White House spokeswoman Claire Buchan said.

If Bush should use this power, he would not be breaking with tradition considering the records of his predecessors.

However, because the president has been so successful in his dealings with Congress, "it probably will show a little slippage," Fortier said.

Fortier said the president would not face any political embarrassment with the use of his veto unless he is overridden by his own party, a scenario Fortier described as unlikely. To override a presidential veto, the House and Senate must each come up with two-thirds majorities.