I don't disagree, but a) what could he have done? b) when did it become apparent? And c) was there anything, say, a recession or the ACA, that was going on at the time that might have influenced his ability to to that?
Well, look at the situation.... Obama nominated Garland on Mar. 16. Fast forward to Sep. 29 and the Senate was leaving town to go on the campaign trail without having acted on the nomination. There were 54 Republicans - and 24 of those seats were up for re-election. Two of them - Coats (R-IN) & Vitter (R-LA) - were retiring, so that means 22 of the 54 Republican Senators were actively on the campaign trail.
Now in the very
first pro forma sitting of the recess [presided over by Acting President pro tempore Cassidy (R-LA)] at 10:30 am on Oct. 3, Vice President Biden could have walked into the Senate chamber, claimed the gavel from Senator Cassidy, and immediately recognized Senator Reid's point of order that a quorum wasn't present. According to
Senate Rule VI, that would have immediately resulted in a call of the roll to ascertain a quorum. Given that everyone was out of town, it's very unlikely that a quorum could have been mustered - even with the assistance of the Sergeant at Arms - and therefore the only order of business would have been to recess until the next pro forma session (Oct. 6) at which point the very first order of business would have been an automatic quorum call. Now the question here is whether the Republicans could have gotten 51 of their Senators to show up on Oct. 6 and vote "yea". I think that would have been a doubtful proposition.
First off, Collins and Murkowski were already on record as saying Garland should have gotten a vote. Plus, Murkowski was running for re-election... so she had an additional excuse to not make the trip from Alaska to DC, just to answer a roll call when her name came up. So that brings the available Republican number from 54 down to 52.
As mentioned above, 22 of the Republican incumbents were up for re-election... and most of them were in pretty safe seats. But not all of them.
Ayotte (R-NH) and Kirk (R-IL) actually ended up losing their re-election bids... but they wouldn't have known they were going to lose. From their perspective, they were in hard-fought fights... so I can't see either one of them being willing to lose time on the campaign trail to block Garland's nomination.
But there were also 3 Republican incumbents who ended up winning by less than 5% - Toomey (R-PA) won by 1.43%; Blunt (R-MO) won by 2.79%; and Johnson (R-WI) won by 3.36% - so they were in tough fights as well. You've got to wonder how much losing time on the campaign trail to make the trip to DC would have cost them at the polls.
So could the Republicans have mustered the 51 votes? Maybe if they
really turned the screws. But odds are pretty good it would have cost them the majority.