I hate to disappoint and discourage you, but there is no way Republicans will ever impeach him. The best we can hope for would be for a bipartisan group of senior politicians to pay him a visit, tell him he’s lost their support, and “strongly suggest” resignation. This may sound absurd, but if Obama is perceived as severaly damaging the Democrat party, believe me they will take whatever actions they have to (short of impeachment) to remove him to put out the fire. At that point its a matter of political survival.
It is not absurd, and the "preference cascade" may already have begun.
Remember when Obama abruptly flew to Washington during the first days of his Martha's Vineyard vacation? It's still a mystery as to why he did this. Perhaps there was a meeting in which prominent Democrats asked him to a)start to deal with ISIS, and b)back off the immigration amnesty issue?
He is destoying the party, clearly, maybe it took them this long to realize it. At any rate, if I'm right and such a meeting occurred, then it's just a matter of time before he's asked to contract some mysterious illness that won't permit him to continue in office.