Donald Trump. AP Donald Trump is right to be mocking the Ted Cruz-John Kasich deal to cooperate against his candidacy.

The agreement between the Cruz and Kasich campaigns is that Kasich won't spend time or money in Indiana, while Cruz will back off in New Mexico and Oregon. The idea is to consolidate anti-Trump support behind one candidate in each state in an effort to beat him.

But the deal is doomed because it apparently doesn't include the most important part of a strategic voting pact: actually telling your voters to vote strategically.

The best case study for strategic voting this year was in Ohio, where Marco Rubio openly told his supporters to vote for Kasich, not him. This pushed Rubio down to just 3% of the Ohio primary vote. But there are four reasons to think that the Ohio story won't repeat — and Kasich voters in Indiana will not actually shift en masse to Cruz.

1. Unlike Rubio, Kasich won't actually tell his supporters to vote strategically. I can't overstate the importance of this. Kasich can't even bring himself to tell his Indiana supporters to vote for Cruz. You can't have a strategic voting pact without telling your voters to vote strategically!

"I've never told them not to vote for me," Kasich said on Monday, when asked what his supporters in Indiana should do. "They ought to vote for me. But I'm not over there campaigning and spending resources."

Off message!

2. If you were a Rubio supporter in Ohio, the thought of voting for Kasich probably didn't make you want to puke. But a lot of Kasich supporters are nauseous at the thought of Cruz. Kasich's supporters know that he is far behind and stands little chance of winning the nomination, and they're voting for him anyway. Why? Because they can't bear to vote for Trump or Cruz.

In comparison, Rubio and Kasich appealed to demographically and ideologically similar voters. Kasich, the Republican governor of Ohio, is very popular with Ohio Republicans, especially the establishment type of Republicans who might have backed Rubio.

Strategic voting is harder to pull off if lots of your voters strongly dislike the guy they'd have to vote for strategically.

3. Rubio's support had already collapsed, but Kasich's is building. Maybe Rubio's 3% haul in Ohio didn't actually reflect that impressive a shift in his voters to Kasich. On the same day, he took just 6% of the vote in Missouri and 8% in North Carolina, despite not having surrendered there.

If Rubio's supporters were abandoning him organically, driven away by the stench of the death of his campaign, then that isn't likely to similarly happen with Kasich's voters. After all, Kasich has been improving in national polls.

4. Shifts of campaign resources aren't that important. Without an explicit call from the candidate to vote strategically, what does the "deal" mean to voters? Well, in Indiana, it means they'll see fewer Kasich television ads, no local Kasich campaign rallies, and less spending from Kasich on get-out-the-vote efforts.

But those sorts of traditional campaign elements have been less important than usual in this race.

Consider New York. Kasich won my home precinct with 56% of the vote, and placed second in the state overall despite the apparent nonexistence of the Kasich campaign in my neighborhood.

I received no mail from Kasich, saw none of his ads on television, and received no knock at my door from any of his supporters. The closest my neighbors got to direct Kasich campaigning was his sandwich-fest in the Bronx. Yet he still managed to win Manhattan.

This campaign has been mostly conducted in the national media, and where Kasich has shown strength has been by getting his message out through national media. The message there remains that Kasich fans should vote for Kasich.

So that's why the pact doesn't work and why Trump is still likely to win Indiana, where recent polls show him leading by about six points.