IF THE PRESIDENT OF THESE UNITED STATES, SIGNED A BILL INTO LAW, THE HOUSE AND SENATE HAD TO PASS IT AND SEND IT TO HIM.
that is not strictly accurate. the president can do certain things by executive order. while his orders are not bills and not technically laws, as they can be overturned or expire, the carry the same weight. FDR rounded up Japaneses by executive order. this was clearly unconstitutional, but it was done anyway. worse, it was done by the military...so violated the constitution in two ways.
the emancipation proclamation carried the weight of law at the time but was not legal.
another way that presidents get around congress is through the alphabet agencies. they have broad powers and little oversight. the best congress can do with them is defund them. otherwise, they pretty much carry out the wishes of the president or other cabinet members.
all branches of government scramble for power.....and we let them. none of them are supposed to have more power than the people, but the people traded power for free stuff.