What is the best way to set up a partnership between two lawyers, one practicing in DC and the other in Seattle?

There is certainly no "one way" to accomplish this. I suggest reaching out to several business lawyers by phone and discussing your objectives in more detail. Depending on your expected revenue you may choose to set up as a PC vs PLLC. The ethical requirements vary but it is really just a question of procedure in that regard and understanding the general issues of concern, e.g., the name of the firm may be required to contain at least one name of a licensed lawyer in the state. This kind of thing you will want to know upfront. Get some specific insights before you commit. Best regards, Frank Natoli-Lapin, LLC

I agree with the prior answer. You should reach out to a business attorney to discuss your objectives in more detail and the options that are available given your objectives and the restraints on you (i.e. ethical obligations).

I agree with both gentlemen, however, you may want to look into the Swiss Verin Model, that is commonly utilized by many white shoe firms and becoming increasingly popular. This model allows you to use a common platform but minimize or isolate liability to individual offices.