FACTBOX: Scenarios in U.S. political race

(Reuters) - Democrat Barack Obama easily won two more nominating contests, extending his winning streak over rival Hillary Clinton and building momentum in a hard-fought U.S. presidential race.

Republican presidential candidate John McCain, the all-but-certain nominee of his party after rival Mitt Romney dropped out, defeated former Arkansas Gov. Mike Huckabee in Washington state.

Here are some scenarios for the presidential nomination battle in the coming weeks:

* Illinois Democratic Sen. Obama, who emerged from the 24-state Super Tuesday battle on February 5 in a virtual draw with New York Sen. Clinton, added wins on Tuesday in Wisconsin and Hawaii to his hot streak of eight recent victories.

But since Democrats distribute delegates among candidates in proportion to their vote statewide and in individual congressional districts, those who lose a state can still come away with a big chunk of delegates.

By the end of February it is likely neither Clinton nor Obama will emerge with a significant lead in delegates. Clinton is focusing on contests in delegate-rich Texas and Ohio on March 4 as her best chance to gain ground on Obama.

* Clinton, a former first lady, is well known to voters and once had a big lead in national polls, even as Obama won early state contests in Iowa and South Carolina and gained momentum with celebrity endorsements and huge crowds. A longer campaign could benefit Obama as he gets a chance to introduce himself to more voters.

* A close contest could hinge on nearly 800 Democratic "superdelegates" who can support the candidate of their choice. Clinton and Obama are avidly courting those elected officials and party insiders, who account for one-fifth of the party's 4,049 delegates.

* In the Republican field, McCain, an Arizona senator, emerged from Super Tuesday with a commanding lead over Romney, a former Massachusetts governor, and Huckabee. McCain's position as presumptive nominee was all but sealed by Romney's withdrawal, but many conservatives remain skeptical of McCain because of his views on illegal immigration, campaign finance and for having originally voted against President George W. Bush's tax cuts.

* Huckabee, an ordained Baptist minister who is strong in the South and among evangelical Christians, has said he will remain in the race until McCain clinches the nomination.

(Reporting by Joanne Allen, editing by Eric Beech)

(For more about the U.S. political campaign, visit Reuters "Tales from the Trail: 2008" online at http:blogs.reuters.com/trail08/)