With Nothern Democrats in the Senate and Congress and no attempts to impeach?
Stephen Douglas led the Northern Democrats in backing Lincoln, after he succeed in baiting the Confederates into bombarding Fort Sumter.
Considering Lincoln's political persecution of his northern democrat opponents it is safe to say that had any tried to do so they would have been imprisoned and persecuted. Simply look at the records. Lincoln had a congressman from Maryland thrown in prison and another from Ohio deported from the country for opposing him. The latter, Clement Vallandigham, was nationally recognized as the leader of the northern Democrat faction that opposed Lincoln. Lincoln also had Indiana Senator Jesse Bright - a well-regarded northern democrat - expelled from that chamber for sending a single letter to Jefferson Davis that urged peace (note that this sort of correspondence was in no way out of the ordinary among northerners...so long as they toed Lincoln's line. Lincoln himself personally corresponded in secret with Alexander Stephens and one of his agents, Frank Blair, even arranged a secret meeting with Davis in Richmond during the middle of the war). Former U.S. Senator William Gwin of California was arrested in Panama by Lincoln's agents while en route to the east coast. Both U.S. Senators from Missouri were replaced by Lincoln henchmen after they forcefully seized control of the state government in Jefferson City and expelled all the elected officers of the state in 1861.
The message to any congressman who opposed Lincoln was very clear: try anything I don't like and you'll be thrown in jail.