CNN  —  The 2024 Senate map presents a daunting challenge for Democrats. Time will tell if it proves to be insurmountable. The party, which currently holds a narrow 51-49 majority, must defend 23 of the 34 seats up for grabs this cycle. That means Republicans need a net gain of just one or two seats to retake the Senate, depending on which party wins the White House in 2024. The most favorable political terrain for Republicans runs through three states that former President Donald Trump carried by at least 8 points in 2020 – West Virginia, Montana and Ohio. In all three, Democrats have incumbents with unique political brands who…