evidence: Trump, Biden said, "came here with your senator, Ron Johnson, literally holding a golden shovel, promising to build the eighth wonder of the world." [...] Wednesday was Biden's fourth trip to Wisconsin so far this year, an indication of how central the state is to the President's reelection roadmap. Wisconsin is a pillar of the so-called blue wall with Michigan and Pennsylvania - all three of which Trump won in 2016 and Biden flipped four years later. In 2020, Biden won Wisconsin by fewer than 21,000 votes. And with a similarly small margin expected to select the 2024 victor, several advisers and former Biden officials have said that striking the right policy tone with moderates this year - without alienating the party's base - is paramount.