As he gathers with other movers and shakers at the White House on Thursday afternoon to witness President Barack Obama's signing of the Jobs Act, AOL Inc co-founder Steve Case is already thinking ahead to the next cause he can help champion behind the scenes: immigration reform.

Our work's not done, Case told Reuters in an interview, adding that he would still pause to celebrate the passage of the Jobs Act, intended to help start-up companies raise money and hold initial public offerings. Case lobbied heavily for the new law, milking his connections in the Washington area to build consensus around the legislation.

Now that the Jobs Act is completed, making it easier for highly skilled immigrants to work in the United States is one of the most important issues facing the startup community, said Case, who runs Revolution LLC, a Washington-based venture investment firm. Revolution focuses on Internet plays and has backed companies ranging from deals company LivingSocial to short-term car-rental service Zipcar Inc.

Like many entrepreneurs, he favors legislation that would focus solely on skilled immigrants rather than trying to wrap in the contentious issue of illegal immigration.

Case believes there is a chance Congress could act before the November elections, given the success of the Jobs Act.

The biggest battle was around the skepticism anything could get done in Washington in an election year, he said. Momentum begets momentum.

But a narrowed bill may be controversial among some groups. Many constituents including Hispanic voters do not want to separate the issues of highly skilled immigrants from illegal immigrants, believing that pairing the two is the only way that action will be taken on the more difficult issue of illegal immigration.

Despite Case's optimism, Congress remains highly divided, with many members reluctant to pass anything that could be seen as a boon to Obama.

Immigrants founded or cofounded almost half of the 50 top venture-backed companies in the United States, according to a December study by the National Foundation for American Policy.

Of those 50 companies, 23 had at least one immigrant founder, the study found. In addition, 37 of the 50 companies employed at least one immigrant in a key management position such as chief technology officer.

Companies with immigrant founders include some of Silicon Valley's hot startups, such as textbook-rental service Chegg, founded by Indian Aayush Phumbhra and Briton Osman Rashid; online craft marketplace Etsy Inc, founded by Swiss entrepreneur Haim Schoppik; and Web publisher Glam Media, founded by Indians Samir Arora and Raj Narayan.

The countries that supplied the most founders included India, Israel, Canada, Iran and New Zealand, the study found, and the immigrant-founded companies created an average of 150 jobs.

The study looked at the top 50 venture-backed companies as measured by research firm VentureSource, based on factors such as company growth and the amount of capital raised. VentureSource considered only companies valued at less than $1 billion.

Case, who stepped down from the board of what was then called AOL Time Warner in 2003, rules out any eventual run for office. He said he sees his role as a bridge-builder between the political parties and investors.

Revolution is really the main event, he said. That's my core competency.

(Reporting By Sarah McBride and Laura MacInnis; editing by Matthew Lewis)