“According to Executive Vice President Treby Williams '84, the expansion will be the ‘most ambitious and comprehensive’ in the University’s history.” The change is such that Lake Carnegie will be the geographical center of the campus once complete and alter the Princeton culture in ways that could be radical. The question is, is the change ultimately good for the university and the students?
Is this driven in part by a desire to thwart further tax measures on large endowments ?
Transfers & now this ! Well there goes the neighborhood ! 
The Trump administration’s endowment tax applies to schools with endowment per student ratios in excess of $500,000.
Princeton’s endowment was estimated at $23.6 billion in June 2017. If you do the math, Princeton would need to enroll approximately 48,000 students to bring its endowment per student ratio down to a low enough level to avoid the tax.
Princeton’s current enrollment is about 8,000 students. So they would need to add about 40,000 more students to avoid the tax. Adding 500 more students is not going to move the needle.
If Princeton puts its massive endowment to use by adding hundreds of additional students, that could be good from a PR standpoint. Perhaps that is an unspoken part of the rationale. But even if it is, there will be zero practical effect in terms of the endowment tax situation.
Incidentally, there actually is a school in Princeton that may want to adjust its enrollment in response to the endowment tax. But it’s Princeton Theological Seminary, not Princeton University.
The Seminary, like the University, is well above the $500,000 endowment per student level. But it has a much lower enrollment, of about 550 students. Schools with fewer than 500 students are completely exempt from the endowment tax, so PTS could theoretically avoid the tax by cutting enrollment by 10% or so. And in fact, PTS has been thinking about downsizing, although there a number of other financial factors involved besides the tax.
http://www.towntopics.com/wordpress/2017/04/12/princeton-seminary-facing-financial-challenges/
@Corbett: Thank You. I am familiar with the tax specifics & with Princeton Theological Seminary’s situation. Great posts !
My point that I failed to express adequately is a concern among universities with large endowments over higher & more far reaching taxes or IRS penalties as a follow up to the initial tax measure. This is why some organizations (such as the NRA) fight tooth & nail over any measure of increased regulation–because it opens the gates to more comprehensive regulations.