Question: Clinton brings a diversity suit in federal court against Fisk for negligence. To prove Fisk's negligence, Clinton offers 2 days of testimony by an eminent (and expensive) expert on accident reconstruction. Clinton wins at trial and moves to collect as "costs" a $10,000 fee he paid to the expert to review the facts, perform experiments, and prepare for trial. The relevant federal statute, 28 USC 1920, provides that the prevailing party may recover certain limited types of costs of suit from the losing party. These costs include an attendance fee for witnesses who testify at trial but do not include a provision for recovering an expert's fee for preparing for trial. By contrast, a state statute provides that the prevailing party in a negligence case may recover the full costs of retaining expert witnesses.

1. Is there a conflict between the federal and state statutes?

2. How should the judge rule on the motion?

Analyze this problem under Hanna v. Plumer (1965). Please explain/elaborate on answers for 1 and 2. Also, for 2, is recovering costs a procedural or substantive issue and why?