DALLAS - The first national Tea Party convention meets this week to take aim at all the raucous movement says is wrong with Washington and Sarah Palin, darling of America's conservatives, will help lead the charge.

Tea partiers grabbed headlines last year with often highly charged protests against President Barack Obama's healthcare reform drive, his $787 billion economic stimulus package and other aspects of his agenda.

The movement takes its name from the historic protest against British taxation, the Boston Tea Party, one of the triggers of the American revolution against colonial rule.

Organization for the convention in Nashville has been plagued by in-fighting, pullouts and criticism of an attendance cost of more than $500 and a glitzy dinner that evokes Wall Street rather than Main Street.

It also brings together activists who make for an awkward fit, mirroring wider divisions in a movement which seems united in little but its opposition to big government, especially under Obama's Democrats.

Conservatives ascribe the movement to grass-roots frustration with the big spending ways of both Democrats and Republicans. Liberals counter that it is a Republican Party or corporate front.

Some have tried to portray this movement as a commercial endeavor rather than the grassroots uprising that it is. Those who do so don't understand the frustration everyday Americans feel when they see their government mortgaging their children's future with reckless spending, Palin wrote in an opinion published on Wednesday in USA Today.

Palin said she will donate her fee as keynote speaker at the convention to the cause and its candidates.

There is no reliable estimate of the movement's nationwide numbers though strands of it are coming together under different umbrellas such as the National Tea Party Coalition.

ROOM TO GROW?

Some want it to grow from boisterous agitation to a political machine that can get out the vote for candidates who subscribe to its view of limited government.

Activists interviewed by Reuters said they were targeting Democrats made vulnerable by Obama's sinking popularity. All 435 seats of the House of Representatives and more than a third of the 100 Senate seats are up for grabs in November.

In the House, Colorado Democrat Besty Markey is frequently cited as a target while in Arkansas tea partiers in neighboring Texas have signaled their desire to send volunteers to campaign against Democratic Senator Blanche Lincoln, who faces a tough re-election campaign.

They have said they may try to influence Democratic contests by pushing for conservatives within the party to win nominations to run for state or national offices. Activists have said they have their eye on the race in Connecticut to replace retiring Democratic senator Chris Dodd.

What we are working to do is engage people in the process and we are actively recruiting people that have this limited government view. At the same time we are working on training them up to effect political change, said Ken Emanuelson, who is on the steering committee of the Dallas Tea Party.

The Dallas group is organizing local activists by their zip or postal codes enabling them to their work such as voter registration drives in their own backyards.

Paul McGovern, 62, a small businessman in Irving, Texas, who is a volunteer with his local Tea Party group, said he saw the benefits of taking things to the next stage by organizing politically in many ways including on-line.

Obama used the Internet to get elected but now it's his own worst enemy because we'll use it, he said on the sidelines of a tea party leadership conference last weekend in Dallas.

The tea party movement has drawn a mixed bag of what critics might call malcontents, and such a structured approach may grate with libertarians among the faithful.

It is inherently difficult to organize libertarians, which most of the Tea Partiers are, said Cal Jillson, a political scientist at Southern Methodist University in Dallas.

IN-FIGHTING

Mainstream conservative groups such as Judicial Watch, which pushes for government transparency, will rub shoulders with fringe elements such as birthers who insist that Obama was born in Kenya and his administration is therefore illegal.

Organizers say Palin's speech at the steak and lobster dinner on Saturday night will be broadcast live, giving the former Alaska governor and 2008 Republican vice presidential contender a chance to rally activists nationwide.

Commentators credit the movement with generating some of the energy behind the Senate election upset in Massachusetts last month when Republican Scott Brown captured the late Edward Kennedy's seat in a sign of voter discontent with Democrats.

If it does manage to transform itself into a political machine, its impact may be most felt during the primaries when candidates compete for party nominations to run for state or national offices.

The field in the primaries is more fluid which can work to the advantage of a diffuse movement. In Florida, it is credited with a surge in the polls by tea party favorite Marco Rubio, who is vying with Republican Gov. Charlie Crist in the party's primary to contest for a U.S. Senate seat.

(Editing by Anthony Boadle)