As the Nov. 4 election day draws closer, labor unions have been steadily upping the amount of money spent in races across the country, with much spent in support of Democrats who are working to maintain control of the Senate.

In New Mexico, for example, labor unions topped the donor list for the Patriot Majority New Mexico Super PAC, giving about $987,000, according to the Associated Press.

The largest donors include the American Federation of State, County and Municipal Employees, who gave $400,000 to the PAC, a National Education Association Advocacy Fund, who gave $337,500, an American Federation of Teachers' political committee, who gave $200,000 and a PAC of the Southwest Regional Council of Carpenters, who gave $50,000.

The PAC, which raised a total of nearly $1.1 million the past month, has been mainly running radio ads and sending mailers to voters in New Mexico, and they have the Republican Party in their crosshairs.

"Our goal is to prevent a Republican Legislature from doing to New Mexico what a Republican Congress has done to our country," Craig Varoga, the PAC's president and a Washington, D.C.-based Democratic strategist, said Monday in an email statement to the Associated Press.

Patriot Majority USA was described by the Center for Public Integrity as the "largest Democratic-aligned dark money operation in the country," adding, "Every dollar has fueled negative messages that call for the defeat of Republican politicians."

In Connecticut, organized labor is making similar efforts to aid Gov. Dannel Malloy in his re-election campaign against Republican businessman Tom Foley, as many unions favor Malloy's views on collective bargaining rights, paid sick leave and minimum wage increases.

According to reports filed with the State Elections Enforcement Commission, as of last week, Washington, D.C.-based unions had contributed at least $1.9 million to the Connecticut Forward independent expenditure PAC.

Many of those same unions have also contributed tens of thousands to the Connecticut Working Families Party's PAC, which has endorsed Malloy for a second term, reported the Associated Press.

One of the larger unions contributing to Connecticut PACs is the American Federation of State, County and Municipal Employees, which has contributed close to $1 million.

According to most recent spending data compiled by the Center for Responsive Politics, as of Oct. 14, the top three biggest outside spending groups in 2014 are all Democratic-leaning - the Democratic Congressional Campaign Committee at $35,274,257, the Senate Majority PAC at $35,116,177 and the Democratic Senatorial Campaign Committee at $34,301,231.

In 2012, union spending alone equaled $23,913,872. Social welfare groups have spent the most in 2014, at $63,044,783.