PROVIDENCE, R.I. (AP) — They are trying to be hopeful, but the Democratic Party's most passionate voters are struggling to hide their frustration with President Barack Obama.

Republicans may attack the president as a big-government liberal, but many liberals meeting Thursday at Netroots Nation — an annual convention likened to "a giant family reunion for the left" — argue that Obama hasn't fought hard enough for progressive priorities on taxes, health care and the economy. Even more problematic for the president is this: With the election just five months away, some are threatening not to donate money or time or even vote in November for the man who overwhelmingly ignited their passions and captured their imaginations four years ago.

"I want to be happy with him," said Democrat Kristine Vaughan, a 45-year-old school psychologist from Canton, Ohio. "But I am finding that he has succumbed to the corporate influence as much as everyone else. I think he has so much potential to break out of that, but overall he has been a disappointment."