LAST EDITED ON 09-18-12 AT 02:11 PM (EST)
Interestingly, it depends on the type of PAC (including the so-called Leadership PAC and Super PAC).
A PAC may donate directly to a candidate, but there are strict limits on donation amounts. A SuperPAC, however, does not actually donate to a campaign; instead it incurs expenditures (of only certain types) to promote a candidate. There is also another kind of PAC that is issue position-based only (e.g., pro-life) that must be made without reference to a specific candidate and these are not regulated.
Considering that most of the money is pouring out from SuperPACs...
Technically known as independent expenditure-only committees, Super PACs may raise unlimited sums of money from corporations, unions, associations and individuals, then spend unlimited sums to overtly advocate for or against political candidates. Super PACs must, however, report their donors to the Federal Election Commission on a monthly or quarterly basis -- the Super PAC's choice -- as a traditional PAC would. Unlike traditional PACs, Super PACs are prohibited from donating money directly to political candidates.
In addition to direct contributions to federal candidates and the national parties, many organizations also spent money on their own to influence elections. Strict rules govern these expenditures and they must be reported to the Federal Election Commission. There are two kinds:
Independent expenditures are ads that expressly advocate the election or defeat of specific candidates and are aimed at the electorate as a whole. Under federal rules, these expenditures must be made completely independent of the candidates, with no coordination, and they can only be made by the organization's PAC.
Internal communication costs are internal political messages generally aimed only at the members of a union or organization, or company executives. These may be coordinated with the candidates and can be paid for directly from the organization's treasury.
Not included in these totals are funds spent for so-called "issue ads" that don't explicitly call for any candidates' election or defeat. That spending is not reported to the FEC.
OpenSecrets PAC donation tracker
Restore Our Future (Romney) is by far the big kahuna of the SuperPACs, raising almost $90 million, spending over $82 million of that.
Independent Expenditures, Communication Costs and Coordinated Expenses as of September 18, 2012:
Grand Total: $82,491,407
Total For Democrats: $0
Total Against Democrats: $28,484,247 (Obama)
Total For Republicans: $14,015,165 (Romney)
Total Against Republicans: $39,991,995 (vs Gingrich & Santorum during the primaries)
The traditional PAC account for less in donations expenditures, but they can contribute directly toward the candidate, including the candidates' own expenditures (and family staffers and other staffers). There is room here for a lot of gratuity that can go directly to the candidate and their family.
Having said that, there are ways to show your appreciation for your SuperPAC donor (to the tune of a million dollars).