WASHINGTON (AP) – Sen. John McCain swept a string of delegate-rich primaries along the East Coast Tuesday night, reaching for command of the race for the Republican presidential nomination. Hillary Rodham Clinton and Barack Obama swapped victories in a grueling Democratic race.

McCain, whose campaign nearly unraveled six months ago, won in New York, New Jersey, Connecticut and Delaware to gain all 198 delegates at stake. He also put Illinois in his column.

Former Arkansas Gov. Mike Huckabee won in Alabama and in his home state. He also triumphed at the Republican West Virginia convention.

Romney, the former governor of Massachusetts, won a home state victory.

Clinton, seeking to become the first female president, won at home in New York as well as in Massachusetts, New Jersey, Oklahoma, Tennessee and Arkansas, where she was first lady for more than a decade.

Obama, hoping to become the first black president, won in Georgia, Alabama and Delaware as well as his home state of Illinois.

After an early series of low-delegate, single-state contests, Super Tuesday was anything but small – its primaries and caucuses were spread across nearly half the country in the most wide-open presidential campaign in memory.

The result was a double-barreled set of races, Obama and Clinton fighting for delegates as well as bragging rights in individual states, the Republicans doing the same.

Polling place interviews with voters suggested subtle shifts in the political landscape.

McCain held a small edge among voters calling themselves Republicans, a group he had not won in any of the earlier primaries or caucuses. As usual, he was running strongly among independents. Romney was getting the votes of about four in 10 people who described themselves as conservative. McCain was wining about one-third of that group, and Huckabee about one in five.

Overall, Clinton was winning only a slight edge among women and white voters, groups that she had won handily in earlier contests, according to preliminary results from interviews with voters in 16 states leaving polling places. Obama was collecting the overwhelming majority of votes cast by blacks.

Clinton was gaining the votes of roughly six in 10 Hispanics, and hoped the edge would serve her well as the race turned west to Arizona, New Mexico and California, the biggest prize with 370 delegates.

Alabama and Georgia gave Obama three straight Southern triumphs. Like last month’s win in South Carolina, they were powered by black votes.

Democrats and Republicans alike said the economy was their most important issue. Democrats said the war in Iraq ranked second and health care third. Republican primary voters said immigration was second most important after the economy, followed by the war in Iraq.

The survey was conducted in 16 states by Edison Media Research and Mitofsky International for The Associated Press and television networks.

McCain was the Republican front-runner, all but unchallenged in winner-take-all primaries in New York, New Jersey and Connecticut. He looked for a home-state win in Arizona, as well.

Democrats Obama and Clinton conceded in advance that neither was likely to emerge from the busiest day in primary history with anything more than a relatively narrow edge in convention delegates.

“Senator Clinton, I think, has to be the prohibitive favorite going in given her name recognition, but we’ve been steadily chipping away,” said Obama, seeking to downplay expectations.

As she voted in Chappaqua, N.Y., the former first lady said, “The stakes are huge.”

Already, both campaigns were looking ahead to Feb. 9 contests in Louisiana, Nebraska and Washington state and Feb. 12 primaries in Maryland, Virginia and the District of Columbia. And increasingly, it looked like the Democrats’ historic race between a woman and a black man would go into early spring, possibly longer.

The de facto national primary was the culmination of a relentless campaign that moved into overdrive during Christmas week.

After a brief rest for the holiday, the candidates flew back to Iowa on Dec. 26 for a final stretch of campaigning before the state’s caucuses offered the first test of the election year. New Hampshire’s traditional first-in-the-nation primary followed a few days later, then a seemingly endless series of campaign days interspersed by debates and a handful of primaries and caucuses.

Along the way, the poorest performers dropped out: Democratic Sens. Joe Biden and Chris Dodd, New Mexico Gov. Bill Richardson and Rep. Dennis Kucinich of Ohio; and Republican Reps. Duncan Hunter and Tom Tancredo, and former Tennessee Sen. Fred Thompson.

Former Sen. John Edwards pulled out of the Democratic race last week, and former New York Mayor Rudy Giuliani left the Republican field.

Edwards offered no endorsement as he exited, instead leaving Obama and Clinton to vie for help from his fundraisers and supporters.

But Obama benefited from an endorsement by Sen. Edward M. Kennedy, who made a series of campaign appearances in California as well as his home state of Massachusetts.

Giuliani quit the race and backed McCain in the same breath, clearing the way for the Westerner in New York and New Jersey.

Giuliani’s departure also made it possible for California Gov. Arnold Schwarzenegger to back McCain. Schwarzenegger said he would not have done so as long as the former mayor was in the race.

Obama and Clinton spent an estimated $20 million combined to advertise on television in the Feb 5 states.

Obama spent $11 million, running ads in 18 of the 22 states with Democratic contests. Clinton ran ads in 17, for a total of $9 million.

Neither advertised in Illinois, Obama’s home state.