Same old Labour

So, there won't be a Labour-SNP coalition.  Unequivocally, no.  It will not happen:

"Ed Miliband has ruled out a Labour-SNP coalition in the event of a hung Parliament after May's election."

Well, that's the message he wanted to send, anyway.  But that's just the BBC's summary.  What did he actually say?

The Labour leader said any alliance would "not happen" as there were "big differences" between the two parties

Ah, see, that's not quite the same, is it?  An alliance will not happen because there are differences between the parties... at the moment.  This isn't a statement of principle, this is a procedural point, that the two parties cannot in practice be reconciled because there are policy differences (as of today, anyway).  The day after an election, when the keys to No. 10 are dangling in front of them, who is to say that Ed might not be "persuaded" to adjust his views on areas where Labour and the SNP differ?  Then, the "big differences" between the parties would have evaporated, clearing the way for an alliance.

Then, immediately after that, there is the "clarification" as to what he really meant:

"There will be no SNP ministers in any government I lead"

None of that rules out the two parties co-operating on the floor of the House to secure specific policy aims, and (in particular) to exclude a Tory government.  It just means that Milliband intends to get his way in Cabinet.  This isn't a promise to the electorate, it is the first shot in the coalition negotiations - a warning to the SNP not to set their sights too high. 

So it's the same old Labour that we are used to from the Blair days.  Say whatever is necessary to get into power, but always make sure to leave yourself a little wriggle room.