What do you think of this Pittsburgh newspapers accusation that Lincoln and his Republican party are the major threats to the disunion of the country

Because Lincoln and his Republican party did not support slavery.

Explanation:

Lincoln with full name Abraham Lincoln was the first Republican President and he was the 16th United States of America President (elected) in the year 1860. Abraham Lincoln was born on the 12th day of the month of February, in the year 1809 in Kentucky, United States of America, unfortunately he was assassinated on the 15th day of the month of April, in the year 1865 in Washington DC, United States of America.

When. Abraham Lincoln became the President, he and his party were not in support of slavery and was also known for preserving the Union.

It was because of his hatred for slavery that later lead to the abolition of slavery in the United States of America although this did not go well with many people at that time.

answer; andrew jackson approved nullification by signing it into law,and john calhoun opposed it saying it was unconstitutional;