WASHINGTON – When Sen. John McCain announced his intention this week to run for election to a sixth term in 2016, he said he was ready for a fight from any challengers who might want to take him on.

He may well get that fight. Political analysts say McCain will almost surely face an expensive campaign with challengers likely from both the left and the right.

Several members of the state’s congressional delegation have been mentioned as possible challengers and state Sen. Kelli Ward, R-Lake Havasu City, has formed an exploratory committee as she considers a run.

The biggest challenge is likely to come from the right, with conservatives like Ward questioning McCain’s ideological credentials while right-leaning campaign groups are already pledging to raise funds for a credible challenger.

“Look, we’ve done polling, a credible candidate has a very solid chance of beating Senator McCain,” said Ken Cuccinelli, president of the Senate Conservatives Fund.

Finding that credible candidate is the first step.

“You know there are plenty of names who have surfaced, and will surface, but who knows if any of them are going to actually run,” said Stu Rothenberg, a political analyst and columnist for Roll Call.

Rothenberg and others said one thing that might keep potential challengers out of the race is money.

“They’ll need to raise many millions of dollars to challenge him,” Rothenberg said.

McCain had just over $2 million on hand at the end of 2014, the most recent reporting period with the Federal Election Commission. First-quarter fundraising numbers are not due to the FEC until next week, but Politico reported this week that McCain added another $1.6 million in the first quarter of this year.

Analysts say that’s a fraction of what McCain can raise – but also a fraction of what he’s going to need for the race.

“I think it’s not unlikely that he will need something in the vicinity of what he spent the last time, which was more than $20 million,” Viveca Novak, spokeswoman for the Center for Responsive Politics said this week.

“He had some of that leftover from his (2008) presidential campaign, this time he’s going to have to raise it,” she said.

Ward, who was not allowed to raise money during the just-ended legislative session, said she is focusing heavily on raising the funds that would be key to any challenge.

Cuccinelli said the money is there for the right candidate.

“There will be more than enough money to go toe-to-toe, getting message out for a conservative challenger,” Cuccinelli said. “I have little doubt that SCF (Senate Conservatives Fund) will bring well in excess of seven figures to a race like this with a credible opponent.”

Few of McCain’s latest re-election bids could be called close. He faced no primary opponent in 2004 and won the 1998 primary 99.67 percent of the vote. A 2010 challenge from former Rep. J.D. Hayworth ended with McCain taking 56 percent of the primary vote to Hayworth’s 32 percent.

McCain won his last three Senate elections with 69 percent, 77 percent and 59 percent of the vote.

In his re-election announcement, McCain touted everything from his work to protect veterans to his ability to help get a cattle-crossing station reopened in Douglas.

Now chairman of the Senate Armed Services Committee, McCain talked about his work to protect military facilities in the state. He cited his repeated warnings about the Obama administration’s “feckless policy” of “leading from behind,” which he said has led to problems in Iran, Russia, Syria and other parts of the globe.

He did not mention his work as one of the eight senators, along with Sen. Jeff Flake, R-Ariz., who designed a bipartisan comprehensive immigration reform bill that passed the Senate but later stalled in the House.

Cuccinelli said McCain’s work on immigration is just one example of how he has moved away from the conservative principles Arizona voters want.

“He is one of the most aggressive, anti-conservative Republicans in the country,” Cuccinelli said. “He takes a baseball bat to conservatives and gives kisses and hugs to Democrats.”

That’s one reason Ward said she is even considering what she concedes would be a “David and Goliath situation” against McCain. She said voters “want people who are going to be representing them, who aren’t afraid to rock the boat in Washington, D.C.”

“A lot of people are out there who are saying it’s time for positive, passionate, principled conservatives to start leading our country, and so that’s why I’m even considering this race,” she said.

For his part, McCain said after his Tuesday re-election announcement that he will be ready for any and all challengers.

“I expect as in every election campaign a tough fight,” he said. “I’ve never minded a good fight and I will look forward to another one if it’s necessary.”