Dec. 15 (Bloomberg) -- George W. Bush, who went longer than any president since Thomas Jefferson before using his veto power, may wield that authority next year to help re-establish Republicans' reputation for fiscal discipline and unify the party's political base.

Republican leaders are encouraging Bush, who is facing a hostile Congress for the first time in his presidency, to oppose Democratic spending plans. They also want him to threaten vetoes over legislation that would order Medicare to negotiate drug discounts with pharmaceutical makers, rescind energy-industry tax incentives and promote stem-cell research.

``We're going to end up with bills that we're not going to like,'' said Candida Wolff, 42, Bush's assistant for legislative affairs. ``The strongest tool we have is the veto threat.''

In the past, the president ``could count on congressional Republicans to stop most measures that he disliked,'' said John Pitney, a government professor at Claremont McKenna College in Claremont, California. ``Now he can count on the Democrats to send him bills that he does not want.''

While Democrats say they will enforce spending discipline, Republicans will be on the lookout for measures the president can cast as budget-busters in veto messages. The goal is to counter the criticism he and Republican congressional leaders received, both within the party and outside it, during their six years of undisputed control.

`Lost Their Brand'

``Republicans have completely lost their brand as the party of fiscal discipline,'' said Patrick Toomey, a former Republican congressman from Pennsylvania who is now president of the Club for Growth, a Washington-based group that backs small-government candidates.

With Bush in the White House and Republicans controlling both houses of Congress, total government spending reached a 12- year high of 20.8 percent of gross domestic product in 2006, up from 18.4 percent in 2000.

From a surplus of $127 billion when Bush took over, the federal budget swung to a deficit that reached a record $413 billion in 2004. The deficit, currently $248 billion, is projected to begin rising again in 2009, according to the non- partisan Congressional Budget Office.

Vetoing Democratic bills, said Toomey, would give Bush an opportunity ``to prove that the Democrats are the big spenders.''

`Moral Boundary'

Bush's sole veto so far came on July 19, when he successfully blocked legislation that would have expanded embryonic stem-cell research. He said the measure crossed a ``moral boundary'' by relying on cells from human embryos. Overriding a presidential veto requires two-thirds majorities in both the House and Senate.

There's precedent for presidents resorting to more vetoes when congressional control shifts. Since the end of World War II, only 64 of 351 vetoes were issued when the president's party held the White House and Capitol Hill.

Presidents often use veto threats to secure last-minute concessions. Bills that are actually vetoed typically fall into two categories: those deemed budget-busters or unwise uses of federal funds, and those a president considers philosophically unpalatable.

Because Democrats campaigned on an expansive plan to aid the middle class, Republican fiscal traditionalists are especially anxious to have Bush oppose their rivals' spending plans.

Allan Hubbard, director of the White House National Economic Council, said Bush will take a hard line on spending next year. ``He would very seriously look at vetoing'' bills that exceed budget targets, Hubbard said.

Same-Sex Partnerships

Budget hawks aren't the only ones calling for a return of the veto. Social-issue conservatives want Bush to veto the stem- cell bill again if Democrats manage to get it to his desk; self- described family-values advocates want Bush to kill any measures that would add sexual orientation to the list of federal hate crimes, repeal limits on homosexuals in the military or grant legal rights to same-sex partnerships.

For the moment, Bush is talking compromise rather than confrontation. The extent to which he resorts to vetoes will depend on whether bipartisan coalitions can be built around some bills -- and whether Democrats find it more politically advantageous to demonstrate a desire to govern or to engage in running ideological duels with the president.

House Speaker-designate Nancy Pelosi, 66, wants to expand college aid, make health care more affordable and provide new retirement-savings incentives, costly items that could trigger a showdown with the White House.

`Looking for Opportunities'

``Democrats will be looking for opportunities to force Bush into unpopular vetoes,'' said Nolan McCarty, a political scientist at Princeton University in New Jersey. ``This will undoubtedly harden the partisan divisions.''

Other issues that might trigger clashes are abortion, limits on terrorist surveillance and moves to repeal Bush's tax cuts.

Big domestic spending bills will be a flash point.

``If the Democrats try to push through a very expensive agenda that will require very large tax increases, then they're setting Bush up for a series of vetoes, each of which will probably improve his approval ratings,'' said Michael Franc, director of congressional relations at the Heritage Foundation, a Washington organization that backs limited government.

``We have principles, and we're not just going to roll over on our principles,'' Wolff said.

To contact the reporter on this story: Brendan Murray in Washington at Bmurray1@bloomberg.net

Last Updated: December 15, 2006 10:01 EST