Purity vs Practicality Issue on Ballot Measures

What if a ballot measure accomplishes something that you believe, but in the process reaffirms an existing regulation that you find odious, but at least doesn't make it worse? Do you support it? This is my quandary with the proposed ballot initiative I regretted signing in yesterday's post regarding Prohibits Political Contributions by Payroll Deductions initiative. Here is what Richard Rider, taxfighter extraordinaire, had to say on my cross-post in the sdrostra comments:

In particular I disagree on the “payroll deduction” prop’s analysis. B-Daddy is concerned about 1st Amendment issues hobbling corporations and unions funding favored candidates. But in reality — if the measure passes – both unions and corporations are still free to give money to IE (Independent Expenditure) campaigns to support or oppose candidates — as long as these funds are not run or influenced by the candidates.

I’m no expert in this area, but I believe unions are CURRENTLY denied the ability to DIRECTLY give money to candidates. I think that currently corporations can directly fund state candidates, but are often prohibited from funding local candidates for office.

Richard makes some great points. At least I have fewer regrets signing the petition. The purist in me wants to say, tough, I don't support any of these limits and believe that sunshine is the best anticeptic. Unions and corporations should be allowed to contribute but it should be made public. But the realist looks for advancing our goals, without betraying core principles. The question is does support for such an initiative betray core principles. I look forward to reading your opinion in the comments.