Q&A with Robert Stack.

• Author: Levin-Epstein, Michael
• Position: Former Treasure Office of Policy deputy assistant secretary for international tax affairs - Interview

Robert Stack served as deputy assistant secretary for international tax affairs in the Office of Policy at the U.S. Department of the Treasury for almost four years before deciding to leave government service. During his tenure, Stack responded to numerous questions from TEI members and recently granted Tax Executive an exclusive interview shortly after stepping down from his position. Here's what he had to say about the challenges he faced, the state of international tax today, and the role of TEI in the international tax community. The Q&A was conducted by Tax Executive Senior Editor Michael Levin-Epstein.

Michael Levin-Epstein: What was the most rewarding part of being deputy assistant secretary for international tax affairs?

Robert Stack: The biggest reward for me was being able to work with the bright, dedicated professionals, both career and the political appointees at Treasury and IRS, including my boss Mark Mazur, the assistant secretary for tax policy, and IRS Commissioner [John] Koskinen. This was extraordinarily rewarding, because the people at IRS and Treasury show up every day thinking about doing the right thing and how to protect the U.S. fisc within the bounds of our authority and the remit that Congress has given us. Taxpayers are extremely fortunate that both IRS and Treasury can attract such great people, and we need to ensure going forward that the resources are made available to sustain this very strong tradition that we have in the United States government of being able to attract, really, the best and the brightest to work on both tax policy at Treasury and tax administration at IRS.

Levin-Epstein: What were some of the more challenging aspects of the job?

Stack: I think clearly for me among my biggest challenges was working with other countries, particularly the EU member states, at the OECD [Organisation for Economic Cooperation and Development] and elsewhere in a highly politicized atmosphere around issues of multinational tax avoidance. The U.S. goal was to keep the focus on working together in a principled way to establish clear, administrable rules to tackle tax avoidance. We were also of the view that defending and upholding the rule of law is the best guarantor over the long term of good tax administration and global economic growth. Unfortunately, some countries pursued narrow self-interest, and the political environment often pushed toward more politicized outcomes that I fear will bring more instability to the system. The EU member states exacerbated these problems through things like state aid investigations and proposing rules that depart from the international consensus reached at the OECD, basically threatening the constructive role that can be played by the OECD. I think this will continue to be an issue for my successor.

BEPS and OECD

Levin-Epstein: Where do...