1. Donate funds to repair the building.
2. Write to the Russian authorities to express your concerns. Here is a list of addresses. Please note that e-mailing is not very effective. It is best to fax or (ideally) send your letter by registered mail, asking for a reply. In that case the authorities are legally obliged to respond. Send your requests for information individually, not as single letters with multiple signatures. In addition, sign one of the petitions (see link list on the right).
Rector Nikolai Vakhtin has suggested that the recent decision to allow faculty to continue teaching in new premises may have been due to the many public displays of solidarity. Thus it is important to keep up polite but firm pressure on the relevant authorities.
Before writing, please make sure you are up to date on the situation: events are moving quickly.
Please also be careful to avoid excessively political formulations unless you feel you have good reason to use them. Although of course the shutdown is related to the general political situation in Russia, there is no evidence that this incident is directly linked to a _systematic_ Kremlin-engineered program to curb academic freedom or Western influence, or that it was ordered by either the incumbent or the (inevitably) future president. And if only for tactical reasons, headings such as "Putin shuts down Western-oriented university" are simply counterproductive. (Thanks to Jeff Weintraub for prompting me to mention this.)
That said, there is a range of views on this topic, both in Russia and abroad. It might be useful to have a discussion on how the current situation ties in with Russia's particular type and dynamic of authoritarianism, and I would welcome contributions on that topic in this blog.