The largest public employee union in the country endorsed President Obama for a second term on Tuesday.

With 1.6 million members, the American Federation of State, County and Municipal Employees (AFSCME) is considered one of the more powerful unions in the country, and it has long been allied with Democrats.

The union echoed the rhetoric of the Occupy Wall Street movement in endorsing Obama’s reelection bid. 

“President Obama is the only choice for the 99 percent. We must put people back to work, make the 1 percent pay their fair share, and protect Medicaid, Medicare and Social Security,” said Gerry McEntee, AFSCME’s president, in a statement. 

{mosads}“Newt Gingrich and Mitt Romney have a prescription for the U.S. economy that was written by the same corporate interests that got us into this mess in the first place. … We believe that American voters are smarter than that and will say thanks but no thanks to their 1 percent agenda and work to reelect President Obama to a second term.”

The union’s international executive board passed a resolution of endorsement of Obama at its board meeting Tuesday.

AFSCME noted that it launched “a one-of-a-kind nationwide campaign” in 2008 to help elect Obama win the White House. It recruited more than 40,000 activists, made more than 6 million calls to members and sent staff to 17 swing states to campaign on behalf of the president.

Labor has traditionally been an ally of the Democratic Party, but unions have at times grown frustrated with the White House’s lack of attention to their issues. The early Obama endorsement from AFSCME, however, is another sign that unions will be on the Democrats’ side once again come November.  

The public-sector union joins other major players in labor, such as the Service Employees International Union (SEIU) and the National Education Association (NEA), to endorse Obama early before the 2012 election. 

Like SEIU and NEA, AFSCME will be a big help to the president’s reelection bid by boosting the ground game — getting out voters and mobilizing union activists in 2012. 

AFSCME can also help with radio and television ads in support of Obama. AFSCME was one of the biggest outside spenders in the 2010 elections, having spent close to $12 million on independent expenditures, according to the Center for Responsive Politics, a campaign finance watchdog group.

An AFSCME spokesman said thanks to Wisconsin Gov. Scott Walker (R) and Ohio Gov. John Kasich (R), coalitions have been built that are similar to the 2008 elections. Further, the spokesman noted AFSCME is the largest union in the AFL-CIO and the first to endorse among the member unions of the nation’s largest labor federation.

—Updated at 1:54 p.m.