He addressed the congress, hoping to persuade them to fund the already developing war against Mexico. By the time Polk delivered this message, conflict had already arisen between the two nation's militaries and became greater incentive for Polk as he used the instability of the situation of "justify his condemnation of Mexico."
The North realized their troops were not ready to fight, so Lincoln called George B. McClellan to be in charge of all federal troops in Washington and told him to forge a new army to take Richmond. The South was over confident.
U.S should try the easy way