By Steve Holland

WASHINGTON (Reuters) - For months, Republican Mitt Romney's presidential campaign was a picture of discipline, charting a relatively steady course for the former Massachusetts governor through a bitterly contested primary season.

In recent weeks, however, Romney's tight ship has not looked so tight.

Romney's missteps on issues such as immigration and healthcare - and images of him on a jet ski during a vacation at his New Hampshire estate this week - have exasperated some supporters who are calling for a shake-up of his staff and worrying he could bungle Republicans' chances of ousting Democratic President Barack Obama in the November 6 election.

The concerns were summarized in an editorial late on Wednesday by The Wall Street Journal, which said Romney's Boston-based staff was "slowly squandering an historic opportunity."

"Mr. Obama is being hurt by an economic recovery that is weakening for the third time in three years," said the Journal, whose editorial page is a barometer of the thinking of leading conservatives. "But Mr. Romney hasn't been able to take advantage, and if anything he is losing ground."

The anxiety over Romney's campaign has been heightened this week by its conflicting messages over his position on a key part of the Supreme Court's ruling that upheld Obama's healthcare overhaul. But it was only the latest example of message problems from a campaign that even some Republicans say is being outmaneuvered by Obama's team.

Last month, Romney struggled to articulate a detailed response to Obama's executive order that stopped deportations of thousands of children of illegal immigrants.

The Republican - who trails Obama badly among Latino voters - still has not come up with an immigration plan that might cut into Obama's lead among Hispanics without angering Romney's conservative base.

Romney's decision to take this week off at his lakeside home in New Hampshire - which led to the photographs of the multi-millionaire zipping around on a jet ski with his wife, Ann - prompted some fellow Republicans to say that Romney had blown a chance to strike a more patriotic theme around the nation's July 4 Independence Day holiday on Wednesday.

Instead, some said, Romney fed a narrative being pushed by Obama's campaign: that the wealthy Republican is out of touch with the concerns of most other Americans, particularly the middle-class voters both candidates covet.

"I don't even think this is his fault," conservative radio talk host Laura Ingraham said. "This is his advisers. This is not Romney, this is the advisers telling him: 'Oh, it's fine. Take a week.' There's no week to spare, we have a country to save."

A TAX, OR A PENALTY?

Of particular concern to conservatives was Romney's policy dance this week over whether requiring Americans to buy health insurance under Obama's healthcare plan should be considered a tax, as the Supreme Court ruled last week, or a penalty.

Although Republicans were disappointed when the high court upheld the healthcare law last week, they took some solace in the court majority's declaration that the fee charged to those who refuse to buy health insurance was allowed under Congress' taxing powers - making the fee a tax.

That allowed Republicans to campaign on the notion that the Obama plan's "individual mandate" amounted to a tax increase.

But on Monday, Romney senior adviser Eric Fehrnstrom said that Romney believed the Obama healthcare law carried a "penalty," not a tax as the high court had ruled.

Fehrnstrom added that under a similar healthcare plan for Massachusetts that Romney backed as governor, the fee charged to those without coverage was considered a penalty, not a tax.

That put Romney squarely in opposition to the view held by Republican leaders of Congress and many Republican voters. Some Republicans said that by continuing to discuss the healthcare ruling, Romney's team was reminding voters of his role in creating the Massachusetts plan - and diverting the campaign from its focus on jobs and the economy, which most Republicans see as Obama's biggest weakness.

On Wednesday, Romney seemed to change course in an interview with CBS.

"The Supreme Court has the final word, and their final word is that Obamacare is a tax," he said. "So it's a tax. They decided it was constitutional. So it is a tax, and it's constitutional."

Some conservative critics of the campaign reacted with dismay.

Conservative radio talk show host Rush Limbaugh told his listeners it was a waste of time for Romney to debate whether the mandate was a penalty or tax. Continued...