For weeks, Russ Feingold has kept quiet about the Dem drive to recall Wisconsin GOP state senators, perhaps because he didn’t want to encourage any speculation that he might be willing to mount his own recall challenge to the biggest Wisconsin target of all: Scott Walker.

But that’s now changing: Feingold is now actively raising money for the Wisconsin recall effort. He just emailed the list of his group, Progressives United:

For months, we’ve watched together as Scott Walker and state Republicans attacked the rights of Wisconsin workers and families, passed an undemocratic voter ID bill, and are now planning economic policies that would benefit the wealthiest at the expense of working families. But now, we have a chance to put an end to Governor Walker’s radical agenda before he does any more damage. The energy is on our side. Now is the time to do everything we can to change the course of our state. With your help, Progressives United will support every single Democratic candidate on the ballot in July. We only need to elect three new state senators to flip the State Senate. Help us put a stop to Scott Walker’s radical agenda. Will you donate $36 to the Democratic recall candidates? With the help of progressives like you, we can begin to move power back to the people of Wisconsin and away from corporate special interests. The next six weeks will prove to be not just a turning point here in Wisconsin, but across the entire country. Starting today, we can make this goal a reality.

Putting aside the question of whether Feingold is considering a challenge to Walker — it’s unclear whether he’s giving it any serious thought — this is another reminder that events are going to heat up in Wisconsin again in a big way. The recall elections this summer will be a major national story that will attract the attention and involvement of key national players on both sides, and will be closely watched as a test run of who has momentum heading into 2012.