As Chancellor, Hitler still felt threatened by the power of two groups - the army and the SA - so he decided to take action
The SA had been a real asset to Hitler in the beginning
They had guarded Hitler from harm and had beaten up political opponents, but now they wanted well-paid jobs as a reward for their loyalty
Rohm, their leader, wanted to merge his 400,000 Stormtroopers with the German army (100,000) and take charge
This alarmed Hitler, as well as the army leaders
A merger of the two would make Rohm incredibly powerful
Hitler really needed to keep the army leaders happy too: he would need their skills if he were to get back the land Germany had lost through the Treaty of Versailles
On top of this, there were rumours that Rohm was about to seize power and take over from Hitler