I'm not saying the compass compensates for it, i'm saying it doesn't matter at all when you're being vectored.
when atc tells you to fly 090, they mean magnetic 090. not true 090, or a fly a ground track of 090.
from the faao 7110.65:

The FAA OCB, which all operators have to know and are tested on before certification as air traffic controller, does not specify only what TRACK he or she wants you to make over the ground or radar screen! Pilots, In order to do that, must mentally apply the variation in that area.
Some aircraft have "adjustable" compasses, which the pilot can apply the variation as he or she flys over the country and then they don't have to make mental calulations as to proper headings to comply with ATC instructions.
How to compensate for magnetic declination when reading a compass. In this example, the declination is 14°E (+14°), so the compass card points to a "north" 14 degrees to the East of true North. To obtain a true bearing, add 14 degrees to the bearing shown by the compass. The operator is only concerned with the bearing that you are from the radar site and which bearing he or she wants you to fly to comply with their instructions.
Hope this clears this up for you sir, I appreciate your reply!