Why did Lincoln address both sides equally rather than favoring the Union only?

He did not want to create further tensions.

Explanation:

Lincoln wanted both the Union and Confederacy to join together under his presidency. This means that he did not want to create a negative tension from the confederacy - something that would impact the side's openness to re-join the union.

In Lincolns inaugural speech he said "This country, with its institutions, belongs to the people who inhabit it. Whenever they shall grow weary of the existing Government, they can exercise their 'constitutional' right of amending it or their 'revolutionary' right to dismember or overthrow it". This shows that he believed in the people making forming decisions for themselves. He believed that we, the citizens of America, should stay together and form a bigger and stronger country than the rest.

Explanation:

when the united states took over

c. reserves power to the states and people