In what way did the anchluss present a challenge to the united states and its allies

It was a direct result of the failure of the American politicians to back Woodrow Wilson sufficiently to ensure a fair and equal application of the Versailles treaty.  Under that treaty, self determination for national groups was supposed to have been available to the Germans in Europe, just as much as the other nationalities.  Vienna and Western Austria should have been incorporated in Germany from the start, and the grievance which resulted from denying this right gave the nazi party a huge boost.

Explanation:

the federal government of the united states was established by the constitution. us is a presidential republic. the president is head of state, head of government and of a two party legislative and electoral system. the supreme court balances the powers of the federal and the state government. yhe executive branch is headed by the oresident. there are two chambers of congress, the senate and the house of representatives. judicial power is exercised by the judicial branch (or judiciary), comprised of the supreme court and lower federal courts. the judiciary's function is to interpret the   constitution as well as the federal laws and regulations.