The National Journal recently launched a new “lobbyist and advocacy” blog, which gathers together 60 experts from some of Washington’s top lobbying firms and advocacy organizations focused on campaign finance, government transparency and public accountability. Here’s our take on  this week’s question: should lobbyists be banned from giving campaign contributions?

While many a lobbyist might be happy to have an excuse to stop writing checks, a ban on lobbyist campaign contributions wouldn’t really give them one. A lobbyist’s clout is measured not just in how many dollars are forked over personally but how much he or she can bundle. Unfortunately, how many dollars lobbyists actually control remains a murky mystery.

Consider this: so far in the 2010 elections, lobbyists have contributed $10.7 million, according to the Center for Responsive Politics. That’s only a tiny fraction of what most PACs and executives associated with industries contribute. For example, the health care sector alone has given $38.4 million; the financial sector, $78.2 million; and the communications sector, $23.3 million.

When you start digging into the data, you find some interesting patterns. A recent joint investigation by the Sunlight Foundation and the Center for Responsive Politics found Sen. Max Baucus had collected campaign cash from 11 major health and insurance firms–and their outside lobbyists as well. (You can see a visualization of this here.) The same investigation showed that Senate Minority Leader Mitch McConnell, R-Ky., collected lobbyist “bundles” from 14 major health care organizations. Sen. John McCain, R-Ariz., actually led the list, with 22 organizations–though much of that money was directed at his presidential campaign last year. (see the full list.)

Meanwhile, new Federal Election Commission (FEC) regulations requiring disclosure of bunding leave far too much to be desired. This report by the Associated Press used data from the Sunlight Foundation’s Party Time project (politicalpartytime.org) to show that hosts for at least 195 congressional fundraising invitations had yet to be disclosed as fundraisers by the candidates who benefited.

We need better disclosure of how lobbyists raise and contribute campaign cash. A first step would be strengthened bundling rules that capture more activity. Disclosure should also happen in real time, on-line rather than in periodic reports often filed months after bundling activity has taken place.