WASHINGTON, July 13 — After the Iraq Study Group report was released last December, offering a blueprint for changing course in Iraq, it rocketed to the top of bestseller lists and more than 1.5 million copies were downloaded from the Internet. But the reader who mattered most, President Bush, quickly shelved it.

Now, with the Bush administration’s own assessment showing limited progress in Iraq and an increasingly exasperated Congress once again debating the future of the war, a growing number of senators from both parties are making a new push to adopt the study group’s recommendations into law.

The effort has rekindled interest in the findings of the study group, which was led by former Secretary of State James A. Baker III, a Republican, and former Representative Lee H. Hamilton, an Indiana Democrat, including the prospect of aggressive diplomatic efforts involving Iran and Syria, while also fueling debate over whether the report is now outdated.

Supporters of the study group plan say that it has the best chance, of the many war proposals ricocheting around Capitol Hill, of unifying Democrats intent on forcing the administration to shift its war strategy and Republicans who have criticized the president but so far refused to vote against him.