AP

WASHINGTON ONE of the nation’s largest unions and an independent Democratic group supporting President Barack Obama launched a joint $4 million Spanish-language advertising campaign on Monday, targeting Hispanic voters.

The ads, sponsored by the Service Employees International Union and Priorities USA Action, argue that Republican presidential candidate Mitt Romney’s policies would benefit the wealthiest Americans at the expense of Hispanics and other working families.

Polls indicate Obama has a large lead over Romney among Hispanics, who are the nation’s fastest growing minority group and usually a reliable Democratic voting bloc. An NBC News/Wall Street Journal poll released last month found Obama leading Romney among Hispanic voters by a margin of 61-27 percent.

Still, the Obama campaign has spent $1.7 million since mid-April on Spanish language ads in Florida, Nevada and Colorado, according to SMG-Delta, a media firm that tracks campaign advertising.

Obama carried all three states in 2008 against Republican John McCain; all are closely contested this time.

Priorities USA Action, founded by two former Obama White House aides, has struggled in fundraising compared with Republicanleaning independent groups like American Crossroads and its non-profit arm, Crossroads GPS. But the group’s partnerships with SEIU and other organizations, including the League of Conservation Voters and the United Auto Workers, help the group compete with the better funded Republicanleaning political action committees.

The political wing of SEIU has given a combined $1 million to Priorities USA Action during the current election cycle.

The Priorities USA advertising partnerships with SEIU have focused primary on Hispanic voters, a key election- year constituency for Obama. The ads released Monday use statements made by Romney, including his assertion that the very poor were not his focus, to try to make the case that the presumptive Republican nominee would be harmful to Hispanics.

The ads will run on television and radio stations in Colorado, Nevada and Florida – all battleground states with sizeable Hispanic populations – throughout the summer.

Meanwhile, the Obama campaign on Monday also released a new online video on what it says is a Romney plan to eliminate police officer, firefighter and teacher positions.

The video asserts that “this approach is nothing new to Mitt Romney — it’s the same one he pursued in Massachusetts.” The video charges that as governor of Massachusetts, Romney cut funding for education and first responders and says that lead to layoffs, even though he expanded the size of state government overall.