(The Center Square) – A new poll shows the race for U.S. Senate in Wisconsin could tighten if undecided voters break for the Republican challenger. The Marquette Law School poll released Wednesday afternoon shows Democratic incumbent Sen. Tammy Baldwin leads Eric Hovde 52% to 47% in both registered and likely voters. However, the poll – which was conduced June 12-20 – showed 17% undecided when allowed to select. In that question, Baldwin leads Hovde even more substantially, 45-38, but the undecideds are greater than the lead. Among registered voters, Baldwin is at 1 net favorability with 45% h…