House Democrats will try again Wednesday to force a vote on immigration reform. They realize they probably will not succeed. But their strategy has another aim, according to liberal advocacy groups: To make immigration a decisive issue in upcoming elections, thereby taking advantage of the growing Latino vote.

Democratic Leader Nancy Pelosi will put the plan into action in the morning, when she files a “discharge petition,” calling for a vote on an immigration bill that has been languishing since last summer. If she and her allies can get 218 signatures, it will compel Speaker John Boehner to bring the bill to the floor, something he has refused to do.

In theory, the petition could attract support from Republicans who have said they want to vote for reform. In reality, it will get few if any signatures from the GOP. The three Republican co-sponsors of the lower chamber's immigration bill, David Valadao and Jeff Denham of California and Ileana Ros-Lehtinen of Florida, told Seung Min Kim of Politico in February that they would not entertain signing a discharge petition. “Very few discharge petitions actually succeed, since it is considered a breach of party loyalty to sign onto an effort from the opposing party,” Kim wrote at the time. There have been seven successful ones in the last 30 years.

Even without the requisite signatures, the petition serves a strategic goal, according to supporters of reform. “The purpose becomes to put a target on the back of Republicans who say they’re for reform but didn’t get their party to bring it up for a vote,” says Frank Sharry of America’s Voice. “It becomes an issue that can be brought up in their reelection campaign.”

America’s Voice has already compiled a list of thirty House Republicans who have made supportive comments about reform—and who progressive groups plan to brand as hypocrites if they won’t sign. Most are from California, Florida, Nevada, and other states where the Latino community is growing rapidly as a share of voters. Immigrant-rights groups are already talking about districts where that changing electoral map could turn the petition—“an esoteric beltway term,” Jeff Hauser of the AFL-CIO acknowledged—into the rallying point for a public campaign.