I'm not sure if he will win, but he should; he's the best choice for the Democrats. He will deliever Southwest Wisconsin, which he has represented in Congress for over 20 years and where his popularity transcends the Trump-mania, while Representatives Gwen Moore (of Milwaukee) and Mark Pocan (of Madison), the other two Wisconsin Democrats in the House, don't have that kind of popularity (or at least, Milwaukee and Madison are 'maxed out' in terms of Democratic support). But I don't think he'll run - precisely because he's been in the House for 25 years; usually politicians either jump from the House to the governship/senate within 2-10 years of taking office in the House, or they stay in the House until retirement. There are exceptions, like Tim Ryan, but that's the usual rule, and it seems unlikely Kind will be an exception, since he hasn't declared his candidacy yet (of course, he could do so later, given that there's a whole year and a half till the election, but you can't be sure he's running until he does).