but what decision he makes will be significant. it will shake up republican politics if he steps aside. these retirements not only could impact control of the senate next year but reshape the institution. one trend we're seeing is loot of institutionalists are hanging up voting cards and who is vying to replace them? trump-loving fire brands. look at moe brooks vying to replace shelby in alabama who is an aproep ray or the, chairman, long-time veteran. >> a boardman who cut the infrastructure deal. the people looking to replace him oppose it. >> i suspect in the end, that's why murkowski runs. she doesn't want to see that happen in her state. but that's why we watch. it's going to be a fascinating cycle ahead. up next for us, the world's biggest security challenge. president biden makes a big offer to australia. and china delivers an angry response.