It will happen if the Democrats think it's the only way they can get ahead politically. If a poll shows that the American people would be more willing to vote for a Democrat than a Republican if the Democrat would only say he/she's sorry they didn't vote to impeach Clinton, the mea culpas would come so fast it would make your head swim.
pigs would be flying right now. It would be nice if Democrats were Republicans, but they just aren't. A different mindset is involved.