John McCain's climate legacy

• The cap-and-trade measures he introduced ultimately failed in 2003 and 2005 (though the 2003 version got 55 votes).

Yes, but: McCain grew less involved with the topic as the years went on.

• This detailed story from Inside Climate News yesterday points out that he didn't work on efforts to craft a Senate bill in 2010, when the Senate's political window to get a bill across the finish line had opened (though its debatable by how much).
• He also voted for an unsuccessful measure that year to thwart the Obama administration's regulatory authority over greenhouse gases.

The intrigue: However, in 2017 he cast the decisive vote when the Senate very narrowly rejected a GOP-led move to kill Obama-era regulations to curb methane emissions from oil-and-gas development on public lands.

• "McCain can be seen on the floor facing off heatedly against a half-dozen GOP senators who surround and block him before he gestures thumbs-down, a foreshadowing of his later decisive vote against the Obamacare repeal," Inside Climate News reports.