EMILY’s List announced Tuesday that it has more than tripled its membership since Republicans assumed control of the House 17 months ago.

The group, which works to elect Democratic women who support abortion rights, started 2011 with fewer than 400,000 members. That number jumped to 1 million by the end of the year, with 500,000 more added during the first five months of 2012.

EMILY’s List President Stephanie Schriock credited the “Republican war on women” with the group’s spike in membership, which will increase its ability to mobilize voters and funnel donations to preferred candidates. The group this cycle has endorsed 11 women who are running for Senate and 33 who are running for the House, including incumbents.

“Women want representatives who will stand up to the right and build a more progressive America,” Schriock said in a statement. “EMILY’s List is supporting a remarkable number of candidates who fit that bill perfectly and our 1.5 million members can’t wait to see them change the face of power in Washington.”