A word of appreciation goes to Sen. Bob Casey, who announced Friday that he won’t seek the Democratic nomination for president in the 2020 election.

In a visit to the Butler Eagle editorial offices 12 days ago, the Scranton Democrat spoke about “an obligation to think about it.” He didn’t elaborate much about the pros or cons of a White House run, but Casey said he did feel a sense of commitment to the third six-year Senate term he’s just beginning. “I think I’m a lot more likely to be a senator than a candidate,” was how he put it.

Casey’s victory over Republican Lou Barletta in November was unprecedented for two reasons. First, Casey is the first Pennsylvania Democrat to win a third Senate term; and second, he regained political ground from President Donald Trump, winning back Erie, Berks and Northampton counties that had swung to Trump and the GOP in 2016.

“If you don’t win Pennsylvania, it’s game over,” Casey told the Eagle editorial team. “And I think I could win the state in a presidential race.”

Casey’s announced decision not to run coincides with a feature story in Friday’s Philadelphia Inquirer about the other Scranton Democrat: Joe Biden. The Inquirer headline said it all: “As Biden mulls 2020 run, his hometown asks: ‘Can his family go through all this?’”

It’s becoming clear that Biden wants the Democratic nomination. And a growing cadre of political fortune-tellers are discerning that Biden is the early choice of what passes these days as the Democratic leadership.

“Joe Biden is Democrats’ flavor of the moment,” contributor J.T. Young writes Friday in The Hill, adding, “in an unknown field likely to be populated by comparative unknowns, he stands out and is frequently listed as Democrats’ top 2020 presidential pick.”

It’s more than just name recognition, according to analysts like Young. They say an ideal presidential candidate should be a political moderate — Biden and Casey both are considered moderate but capable of beating the party’s own growing liberal factions in the state primary

“The key to American presidential politics is winning the center; however, the key to winning today’s Democratic nomination is winning the left,” Young writes. “Thus to aim at America’s center, establishment Democrats would have to avoid a majority of their own party by beating their left.”

Casey’s dividing point with Biden — indeed, with Democratic orthodoxy — is his mixed voting record on abortion. A year ago he sided with Republicans voting for a ban on abortions after the 20th week of pregnancy. Casey’s moderate voting record particularly on abortion might appeal to Pennsylvania’s large concentration of Catholics but not to the rest of a Democratic base that leans pro-abortion as it leans left.

Taking all factors into consideration, Casey chose correctly to focus on his Senate post. There’s no reason to doubt his statement that sense of duty compelled the senator to think about running. Logic and discernment led him to the realization that his duty is best served in the Senate term to which Pennsylvanians elected him — that, and maybe the realization that Scranton isn’t big enough for two presidential favorite sons. For whatever reason, you made a good choice, senator.