How was Jackson victory in the election of 1828 a reflection of a change in American politics

It was the first time a Democratic candidate was elected as a President.

Explanation:

Before 1828, and after the split of the single party system that existed before, the Presidents had been Republican while the Democratic party was only reeling for voter base.

The same candidates fought for the seat in 1824 as well as 1828 elections.

This time Andrew Jackson was able to win over Quincy Adams finally becoming the first Democratic president.

The Democrats would from thereon regularly win elections for President.

the  seven  days  battles  were  a series of seven battles over seven  days from june 25 to july 1, 1862, near richmond, virginia,  during  the american civil war. the  seven  days ended with mcclellan's army in relative safety next to the james river, having suffered almost 16,000 casualtiesduring  the retreat.