The war powers act of 1973 was intended to affect the balance of power between the president and congress by

Short It limited the power of the president and gave congress more power.

Elaboration: The war powers act of 1973 came into place as a result of the actions of LBJ in the Vietnam war, he had been very secretive about how many troops he ordered and how he was conducting the war.  The War powers act of 1973 stated that the president was required to inform congress on war policies/strategies, and the president could not send troops to a foreign power for more than 60 days without declaration of war by Congress.  It was vetoed by president Nixon, but congress passed it over his veto.  This law impacted the role of the president by limiting his/her power when it comes to war.  Today, it essentially acts as another "check" in the system of checks and balances by making sure that the Executive branch (president) does't have too much power over foreign policy.  Hope this helps!