Democrat Senate candidates getting more money than their Republican challengers

Betsy Newmark has the details of how Democrats are outspending Republicans in this year's competitive US Senate election campaigns. Then she summarizes:

Many GOP donors have been scared by IRS targeting and audits of wealthy Republicans, prosecutorial attacks like the one in Wisconsin against Gov. Scott Walker's allies, and the Democratic demonization of GOP contributors. Not everyone has the thick skin of Charles and David Koch.

Many GOP donors try to avoid becoming political targets by writing checks to 501(c)(4)s, which don't have to disclose donor names. But under IRS rules these groups are largely limited to issue ads that don't advocate for or against a candidate. Super PACs like Mr. Reid's can say whatever they want, but 501(c)(4)s can't respond in kind on behalf of GOP challengers.

Read more here.