Presidential races clearer, but no shorter

By John Whitesides, Political Correspondent - Analysis

WASHINGTON (Reuters) - The White House race might be clearer but showed no signs on Wednesday of getting shorter as both parties contend with bitter nominating brawls ahead of the biggest single primary day in campaign history.

The departures of Democrat John Edwards and Republican Rudy Giuliani narrowed the fields of viable candidates to two in each party but did little to fundamentally change the dynamic in hard-fought and potentially lengthy presidential races.

Two dozen states vote on Tuesday, including big prizes like California, New York, Illinois and New Jersey, as the remaining presidential candidates in each party embark on a week-long, coast-to-coast dash for delegates.

"It's going to be impossible on either side, Republican or Democrat, for any candidate to have enough delegates next week to claim victory," said Republican consultant Rich Galen.

Democrats Barack Obama and Hillary Clinton are running neck-and-neck, having split the first four contests. The Edwards withdrawal could rally the anti-Clinton vote and aid Obama in Southern states where Edwards had a base.

"More Edwards people will break to Obama, they were both change candidates," said Democratic consultant Dane Strother, who noted Clinton's sometimes polarizing effect. "Hillary is no one's second choice."

Republican John McCain appears to have a slight upper hand over rival Mitt Romney heading into "Super Tuesday" after his big win in Florida on Tuesday. A third candidate, former Arkansas Gov. Mike Huckabee, hopes to make a dent in a few Southern states.

While Giuliani never developed much of a base, his decision to drop out and endorse McCain could aid the Arizona senator as the pair have similar strengths on national security issues and similar appeal to Republican moderates.