Support for Israel's current government (elections in October 2026) being but one example.
Republicans do this too. Two of the seats they're at most risk of losing are Maine and Alaska held by Susan Collins and Lisa Murkowski (respectively). They currently have 53 votes (well, 52 with Mitch McConnell MIA). That means they can pass things with 50 votes (and JD Vance's tie break) on anything that can get past or doesn't require cloture (eg approving judicial nominations, reconcilation). So, every time you have a controversial nomination or bill, you'll often find Collins and Murkowski vote no because their votes aren't needed. The leadership is insulating them from attack. But when their votes are needed, they're there (eg Collins's required vote to confirm Brett Kavanaugh).
As for the number of Democratic senators who voted against weapons for Israel, it is significant because it never would've happened 5 years ago, but it's also mostly performative because there's no way it was going to pass.
As another example, Democrats did a rare move to invoke the filibuster last year to stop ICE funding. This resulted in a government shutdown and important programs being punitively defunded (eg there was a reserve fund for food stamps that was intentionally not tapped). What happened? The Republicans needed 60 votes to force a vote. There were 52 votes. 8 Democratic senators crossed the floor to vote with Republicans. That's so weird. It's the exact number required. What a coincidence. Whatever that number was, 1, 5, 8, 12, it doesn't matter. There will most of the time be that number of exact senators requried. This, by the way, is part of the rotating villain role within the Democratic Party.
This is how calculated it was. All 8 of those who crossed the floor were either retiring or they weren't up for re-election in 2026 so the voters couldn't punish them. John Ossoff, the current liberal darling, was going to be one of the 8 but he's facing re-election this year so Chuck Schumer whipped another vote to replace him.
Another classic example was the Epstein transparency act. Trump threatened members who signed the discharge petition. Mike Johnson actually shut down the House for 7 weeks to try and get those that did to change their vote. yet when the discharge petition got 218 votes (the minimum required), suddenly the votes in the House and Senate were almost unanimous. Well, if support was almost unanimous, why not just have a vote to begin with?
Mitch McConnell can really be credited with pioneering a new era of obstruction in the Senate. He realized there was a political cost to some votes. Some things were popular and he didn't want to pass them so he'd just make sure they never made it to the floor for a vote.
So my point is that imagine the Democrats control the House, the Senate and the White House in 2029 and that same Israel funding bill came up. Will all those Senators and House representatives vote for it when it might pass and become law? Nope.