No one seems to notice that Democratic voters have been key to Donald Trump’s success in the Republican primaries so far.

How?  Trump has mostly won in open primaries—that is, Primaries that allow Democrats to cross party lines and vote for the Republican candidate. To date, Trump has won in 10 of the 15 decided states.  Eight of Trump’s ten victories were in open primary states: Alabama, Arkansas, Georgia, Massachusetts, South Carolina, Tennessee, Vermont, and Virginia.

Trump also won in New Hampshire, a hybrid state where independents can vote in the Republican primary. His other victory came in Nevada—basically a home state.

That’s a lot less impressive than the media pundits would have you believe.

One analyst argues that, if not for the Democratic crossover voters, Trump would have lost South Carolina’s 50 winner-take-all votes to Ted Cruz. Switch those delegates to Cruz, and Cruz would be beating Trump 276 to 269 right now.

A similar case could be made in Virginia, where Trump beat Marco Rubio by only 29,000 of over a million votes cast. The Republican Party Chairman bragged that his party “blew the Democrats’ turnout out of the water” in a Washington Post article. He’s right. The Democratic turnout dropped by one-fifth.  It’s pretty easy to guess where those Democrats went. Many of them crossed over to the Republican primary and voted for Trump. I wouldn’t be bragging about that if I were the Virginia Republican State Chair.

Trump’s supporters may argue that attracting Democrats shows cross-party support for the general election. Maybe. If so, it only demonstrates the Democrats perceive what many Republicans do not–that Trump is not a true conservative. Cruz and Rubio have argued that point all along.

Nevertheless, polls show that Hillary Clinton would crush Trump if the general election were held today. There can be only one conclusion. Many Democratic voters, confident that Bernie Sander’s threat is kaput, are throwing their weight behind Donald Trump to sabotage Republican chances in November.

The bad news for Trump is that only seven open primaries remain among the 35 remaining contests: Illinois, Indiana, Mississippi, Missouri, Montana, North Dakota, and Wisconsin. The good news for him is that Missouri, Montana and Wisconsin are winner-take all rather than proportional states, an important consideration.

Two key remaining states are hybrids of open and closed primaries. In North Carolina, independents may vote in the Republican primary, but Democrats can’t. In Ohio, voters may change their party affiliation on Election Day. Allegations of foul play will abound.

The primaries on March 5 will be an indicator of Trump’s true strength absent Democratic support.  All four contests are closed primaries or caucuses. Polls show that Trump is ahead in Louisiana, the biggest prize of the day with 47 delegates.. Kentucky, nearly as large with 45 caucus delegates—and holding its first-ever caucus—is an unknown. Trump has been invisible in Kansas, another medium-sized state with 40 caucus votes. Trump chose Maine, with only 23 caucus delegates, for his response to Mitt Romney.  He’s likely to win there.

Today is an important day for Trump. Let’s see if he can show real strength among real Republicans without crossover Democrats padding the ballots.