TNR has a good article about the lack of oversight and transparency in presidential library fundraising, and the potential for abuse it creates. We've seen the problem before:
In 1993, George H.W. Bush pardoned Edwin L. Cox, Jr., who had pled guilty five years earlier to bank fraud. Eleven months later, Cox's father pledged support for the Bush library and is now listed as a donor in the "$100,000 to $250,000" range. Likewise, in the late '90s, Denise Rich reportedly pledged $450,000 to Clinton's library at the same time her ex-husband, Marc Rich, was seeking a pardon for racketeering and tax- evasion charges.
Two things make the problem relevant again today. First, Bush is trying to raise a whopping $500 million for this presidential library at Southern Methodist University in Dallas, which means tons and tons of fundraising now, while Bush is still in office and capable of being swayed on policy decisions by particularly large donations. (By the way, Methodist ministers are appalled at the idea of GWB's library being at SMU.)
Second, Hillary Clinton is running for president while her husband's library is accepting donations. There is a strong system of oversight for presidential campaign fundraising (just see opensecrets.org), but there is nothing you can do if you want to see who is donating to Bill Clinton's library. Surely it is time for the FEC to step in.