The candidates for the Republican and Democratic U.S. presidential nominations are campaigning hard in advance of Tuesday's crucial round of contests in 22 states. VOA's Paula Wolfson reports from Washington that California, New York and Illinois are among the states where voters will go to the polls on the so-called Super Tuesday.

The latest national polls show Senator John McCain pulling ahead in the race for the Republican nomination. At the same time, Senators Barack Obama and Hillary Clinton are running roughly even on the Democratic side.

All three are hoping for a good showing on Tuesday, when voters in almost half the U.S. states will go to the polls.

On Sunday, they tried to reach audiences in as many states as possible with appearances on nationally broadcast television interview programs.

On the Fox News Sunday program, McCain said he is pleased with his current standing in the polls, and with the support he has received from party notables. But he acknowledged he still has a long way to go to win over staunch conservatives.

"The key is to unite the party," said McCain. "We have strong support from people like Jack Kemp, Phil Gramm, and Steve Forbes signed up. We are getting a lot of that kind of good support from across the party, but we have got a lot of work to do."

Former Massachusetts Governor Mitt Romney is trailing McCain in the polls and is counting on conservatives to support his campaign on Tuesday. During an appearance on CNN's Late Edition, he said on many key issues, John McCain is too liberal to be the Republican nominee.

"He is not in the mainstream of the Republican Party and in some respects this is a battle for the heart and soul of our party and, of course, our nation as well," said Romney.

The two remaining candidates for the Democratic nomination are already talking about taking on McCain in the general election campaign. On the CBS program Face the Nation, Barack Obama said he will win both the nomination and the presidency by bringing in new voters who have been disenchanted with the political process.

"I think if we can continue to bring people who have not been voting - younger voters, independents, and even some disenchanted Republicans - then I think we will do pretty well," said Obama.

Obama said Hillary Clinton will galvanize Republicans. But Clinton said she has the political experience necessary to withstand a tough national campaign.

"I have been through these Republican attacks over and over again and I believe that I have demonstrated that, much to the dismay of the Republicans, I can not only survive, but thrive," said Clinton.

During an appearance on ABC's This Week, Clinton stressed general elections are much tougher than primaries, and said she is the best person to lead the party against the Republicans.