It was also a statement against Republican gubernatorial candidate, Meg Whitman, who admitted she didn't vote as often as she should have in previous years.
But some nurses told lawmakers they felt like they were bribed into going.
A hearing was put together hastily on the issue.
"This came to our attention because there was somebody that was encouraged to attend a political activity that they felt uncomfortable with," said state Sen. Bob Huff (R-Diamond Bar). "And then they were told: 'Well, maybe we can give you CE for that.'"
"CE" is continuing education. Like most licensed professionals, nurses must complete 30 units of additional classes every two years to be able to keep practicing.
The California Nurses Association insists no one got continuing education units for attending a political rally. The actual course was separate and clearly advertised as separate.
The flyer says the four-hour course on advocacy before the rally is eligible for up to eight continuing-education units. But the protest and rally were also listed.
The union and nursing board feel such a class is important in advocating for patients.
"We say they have to be related to nursing and they have to be above and beyond that which you were taught in pre-licensure nursing program," said Louise Bailey, interim executive director, Calif. Board of Registered Nursing.
State Sen. Sam Aanestad (R-Grass Valley) is also a dentist and must take continuing-education courses.
"They have to be clinically applicable to patient care," said Aanestad.
But no one could name one nurse who received CE credit.
"Have you had one person received credit for attending a rally?" asked state Sen. Dean Florez (D-Shafter).
In the end, the committee chairwoman said they would hold the bill that would ban CE credit for political activities, but also warned the nurses union to be careful.
"There should be no impropriety, or even the whiff of impropriety," said state Sen. Gloria Negrete McLeod (D-Chino). "If you're going to have CE classes, offer them on another day, not on a day you have a rally."