I'll leave the question of whether President Obama's decision to abandon a planned missile defense of Poland and the Czech Republic is good or bad policy. As a matter of timing, however, it's surely bad politics. There's surely a better day to make such an announcement than the 70th anniversary of Stalin's invasion of Poland.
UPDATE: The NYT reports on the unfortunate timing as well.
SECOND UPDATE: The NYT story linked above no longer makes reference to the timing, but this other NYT story does.