Is it too late for Trump to reverse his crashing poll numbers?

[Beefalow and the Consumer]

[snip]

Of course, the Democratic candidate support is probably lower, too.

June 16, 2016: Clinton 44.9
June 16, 2012: Obama 45.7
June 16, 2008: Obama 45.9
June 16, 2004: Kerry 43.7

Couldn't find a graph to compare over time, so I just compared numbers on the same day. There's not much difference - she's below both of Obama's numbers by 1% or less and is beating Kerry by 1.2%.

When is it that we should expect some clear majority polling results (in the high 40's or low 50s)?

I'm assuming a Bernie Sanders endorsement of Hillary Clinton will come around the time of the convention, maybe before it.  So, we're going to have the following timeline of events:

1. GOP convention disaster.  I have no idea if anyone will even speak on Trump's behalf
2. Bernie goes on record as endorsing Clinton
3. DNC, which will be one giant Hillary commercial, probably featuring a speech by Bernie Sanders talking about the new progressive role in the party, probably throwing his full support behind Clinton.

If the post-convention bump doesn't put her into the low-50s, I'd be very surprised.