According to Slivinski, Reagan's proposed budget was in trouble before the assassination attempt: "The budget was not as well accepted in the Republican-controlled Senate as the White House hoped. The President's opposition in the Democrat-controlled House was having a field day denouncing his supposedly mean-spirited budget."
After Reagan was shot, this all changed:
Attempts to restore money to various government programs that were on the chopping block failed resoundingly. In fact, the main challenge to the budget plan the day after the assassination attempt came from a fellow Republican. Senator John Chafee of Rhode Island offered an amendment that would have restored $1 in funding to numerous education programs, wasteful urban transit programs, home-heating assistance for the poor... and community health programs.
Under different circumstances, many senators of both parties would be rushing to support these programs. Instead, sixteen Democrats joined Republican supporters of the Reagan plan and killed the Chafee bill, 59 to 41. In the end, the Senate approved the basic framework of the Reagan budget by a margin of 88 to 10...
What had happened? The truth is that very few senators - only ten, to be exact - wanted to vote against the budget of a popular president who had just stared down death.
I guess I'll never cease to be amazed by the irrationality of politics. The president takes a bullet from a random assassin, so you change your vote on home-heating assistance for the poor. What? If you thought that government was responsible for keeping the poor warm in the winter, why would you change your mind because one guy "just stared down death"?
The interesting question for me is: Were politicians changing their votes because public opinion changed? Or were they sentimentally sacrificing votes?
Slivisnki seems to think that politicians were basically responding to a shift in public opinion. Reagan's May approval rating was 67%, and...
Even Tip O'Neill practically rolled over. The day before Reagan's speech, he told the press, "Support the President - that's the concern out there - and Congress can read that. I've been in politics a long time, and I know when to fight and when not to fight."
Reagan's budget won, 253-176.
On reflection, the Hinckley Effect is just the rally-round-the-flag effect writ small. But it's even more amazing because the effect is so out of proportion to the cause. A lone gunman sharply changed government policy even though his target survived!