The Urban Dictionary entry:

1. straw dog
In business, something (an idea, or plan, usually) set up to be knocked down. It's the dangerous philosophy of presenting one mediocre idea, so that the listener will make the choice of the better idea which follows.
It backfires with some frequency, as the listener (out of sheer perversity) will insist on the straw dog.

The proposed German translation doesn't fit. It's apparently a thing, not a person (according to the provided source).

Straw man in law
The term straw man can refer to a third party that acts as a "front" in a transaction (i.e., who is an agent for another) for the purpose of taking title to real property or some other kind of transaction where the principal remains hidden or to do something else which is not allowed. A straw man is also "a person of no means," or one who deliberately accepts a liability or other monetary responsibility without the resources to fulfill it, usually to shield another party.

At one time, men of straw were men that could be found in the courts who placed a piece of straw in their shoes (also called straw-shoes). Jurists knew that these men of straw were available to testify for a price, and they would be asked leading questions: Don't you remember that you saw him at the market at the time of the murder? And the straw-shoe's rejoinder would be: yes. Then the straw-shoes would perjure himself for a price in court, just as the jurist had so cleverly (but fraudulently) suggested.

http://encyclopedia.laborlawtalk.com/Straw_ma...

Man of straw or straw man, can have several meanings: it may also mean the same as "straw dog (argument)" but can also be a person esp. in politics or law. As in the last link.(above)
holger: does that correspond to "Strohmann" in German?

Mary, have you seen the various LEO entries for "Strohmann"? ---------->Dictionary: strohmann