I am not a 100% sure, but I think it would be the speaker of the house. Hope this helps
Anvil is a tool used by blacksmiths, and it is the surface on which the object is placed which is worked on with a hammer- stroked with a hammer.
von Bülow meant (in 1899) that Germany will either have to colonize others ( be the hammer) or it would have to risk being colonized itself (being the anvil), hence showing the need for Germany to participate in colonization.
The Spanish would most likely try to recruit allies to defeat the armies of the Aztecs since the Spanish were bent on defeating the Aztecs and conquering Mexico. This would have been a strategy to create hegemony over this part of the New World.
Explanation:
the nations needed resources along with more land as to increase their empire. although risky, like Britain's American colony, they had a lot of benefits if pulled off corectly