What was Union's strategy during the Civil War?

The Union basically followed a strategy devised by the highest
ranking general in the army in 1961, Winfield Scott. A hero in the Mexican War, Scott was too old
to serve in the Civil War, but before he retired, he devised the Anaconda
Plan: a method to slowly strangle the Confederate states. Simply put, Union troops
and the Federal Navy would blockade the South's port cities along the Atlantic coast, the Gulf of
Mexico, and the Mississippi River. Additionally, Union troops would move down the Mississippi
River, and capture all garrisons along the way. Eventually, the seceding states would be
surrounded, except for in the Western theatre (Texas, Arkansas, and Louisiana), which would
effectively be cut off from the rest of the Confederacy. Opponents of the plan who wanted a quick
victory, initially (and correctly) thought that it would be a slow process. However, the
plan--named after the anaconda snake which slowly suffocates its prey--worked perfectly, though
it did take three years for the plan to work--and another year to defeat Robert E. Lee's stubborn
army in Virginia.