"A key campaign skill is raising money," Shields wrote. "Unfortunately, this fact favors the career politician or the insider. Most of the rest of us do not gain this type of experience in our non-political endeavors. To be so totally dependent on raising money for success in running for any office puts a huge premium and advantage on those who do it well. I think successful fundraising says something about a candidate, but it certainly does not say everything about a candidate. To sort our leaders by how good they are at fundraising is a narrow filter indeed.

"It would be easy to say the system is flawed and leave it there, but after my experience, I'm unwilling to say it's that simple," he wrote. "Campaigning, in addition to raising money, is the most challenging thing I have ever attempted in my life. Previous campaign experience would have better prepared us for how to master the many important aspects of the campaign challenge. Should I ever run for office again, I will be much better prepared for these challenges."